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Randall C
Randall C, ASE MasterTechnician
Category: Ford
Satisfied Customers: 12803
Experience:  35 years ASE Master Tech, Diagnostic , Electrical Specialist
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2000 Ford Focus ZX3: crank sensor..faulty..300 and dies while idling.)

Customer Question

I have a 2000 Ford Focus ZX3, 2.0L, duel overhead. Does it have a crank sensor and what would be symptoms of faulty part. (My idle is fluctuating from 750 to 300 and dies while idling.)
Submitted: 5 years ago.
Category: Ford
Expert:  Randall C replied 5 years ago.
Hello, My name isXXXXX will do my best to assist you.

is check engine light on?

does it run ok otherwise?

Customer: replied 5 years ago.
check engine light only comes on for code P O 761 (transaxle solenoid).
It has an occasional 'sputter' in speed on highway, but the idle is constantly rough w/ stall almost every stoplight or sitting.
Expert:  Randall C replied 5 years ago.
well, my first thought would have been a dirty throttle body, very common and will greatly affect idle.. Now,, if missing and sputtering, that may be different and be ignition related like coils ,plugs etc. I would surely do a throttle body cleaning unless,, you are saying the check engine light came on at samne time and may?have a trans problem locking into engine like converter not releasing all the way
Customer: replied 5 years ago.
Yes, 'locking'/not going into overdrive w/out putting in neutral, then shifts. Engine does not set off 'check engine' or show codes. New plugs, wires, cleaned throttle body fully. Replaced main air flow sensor, new air filter, cleaned air flow, no noticeable vacuum leak or hoses 'loose'.
Expert:  Randall C replied 5 years ago.
well, you added all new information so,, have to back up. its not a vacuum leak, that causes high idle. so,, do you feel its trans related affecting engine?

you now say no check engine light but earlier said you did have light and code so i am confused
Randall C and other Ford Specialists are ready to help you
Customer: replied 5 years ago.
A friend pulled off the throttle body and made an adjustment guess and, after spraying the new mass air flow sensor and a couple trips, the idle mostly improved. It still has occasional irregularities cutting off but has improved...still tho, wish would solve. I replaced the SSC solenoid as indicated by the diagram, but the shift to overdrive still gets stuck (actually the diagram mentioned it was the solenoid w/white wire which was different location than larger SSC cylinder so I replace it also.) I don't get it. The diagram was specific and obvious, yet little improvement...I still have to put in neutral at 60+ mph to release gear and dash light (circle/cog looking w/'spokes' appearance) lights up until engine turned off and reset. I don't mind effort and a little money when resolved BUT NO RESULT??!! HELP!!
Expert:  Randall C replied 5 years ago.
I am sorry as was away today and need to step away again in short while. I have to review this, check some things and get back with you. I will be later this evening so please bear with me as we are now at trans problem which is more tricky. Thanks
Customer: replied 5 years ago.
Curiously enough, today driving was better and shifting seemed normal. I guess it takes a couple drives/resets to stabilize? The idling even seems better, but engine running with a few 'stall/jerking' in higher speeds such as cruising. I've checked the new plugs, new wires are not touching and prime-sealed wires anyway. Is there another 'timing/tune-up' adjustment I could do?
Customer: replied 5 years ago.
Sorry it has taken so long to get back to u. (I hope i at least accepted your answer before). The tranny situation has been put off. To clear up the stalling situation, I've replaced the fuel idle sensor (as was suggested by a former mechanic helping my roommates car situation), but now the stalling only occurs 7 out of 10 times instead of 9 out of 10!! To refresh/update previous tries to solve: I began replacing air (emission) parts and spraying fuel intake (carburator?) which eliminated the 'check engine' code for those problems, yet the stalling persisted. It was thought the final solution was the fuel idle sensor part...NOPE! The situation was this: before replacing that part, the engine would run okay during acceleration and mostly coasting speeds (not counting the transmission sticking). The only problem was intermittent idle/stall problems. Sometimes it would idle fairly 'smooth' at approx 650rms consistently then suddenly sputter/stall. After new sensor, still intermittent and occasionally has stalled while coasting 15-20mph. You mentioned cleaning
throttle-body (what/where is that and how to do it?).
Expert:  Randall C replied 5 years ago.
its the item the large air intake hose hooks to with the throttle butterfly as shown below

use carb cleaner and gently spray the inside out, holding the butterfly open to get it clean as well

clean little at a time

Then start, rev and blow out

Clean say 3-4 more times till shiny inside

If gummed up, you will have the exact symptoms you describe

Customer: replied 5 years ago.
Oh, sorry I thought I'd mentioned that previously...It was the 1st thihg I did after replacing the emission air flow sensor and cleaning entire air flow assembly.
So, I guess we're back to 'square 40'. (can you tell my frustration in this matter--been dealing with it 3 months now.
Expert:  Randall C replied 5 years ago.
I need to review all this, think some.

Are you sure you dont want to clean it agaion? low idle ? this can cause this but you have more symptoms I need to think about.

Please add ALL things you have done and tried as well as current symptoms one more time for me.Thanks
Customer: replied 5 years ago.
Replaced air flow sensor inside air chamber assembly and sprayed again recently with air flow cleaner spray. New air filter and recently sprayed fuel intake (carburetor)again, tho just a short spray because a while back it was the first thing I did after replacing the air sensor didn't work, and the engine ran very rough for a bit. Could be I did too much and not enough cycle of spray/crank start. It seems that if the idle rmp.s could be increased above 700 to about 1000, that it would remain stable. It'll sometimes (after warm-up when normally high idle) run a higher rpm steadily but then (like a short?) decrease rpm quickly to sputter/stall. When re-start w/out pressing gas peddle, will not remain idling until started and pushing peddle. Most times I have to put it in neutral at stops while slightly increasing fuel with pedal and holding....even then, it has stalled before. Curious thing I'd mentioned before was the possibility of a short somewhere? Puzzling thing tho is its only the idle.
Expert:  Randall C replied 5 years ago.
I suppose we need to see if running lean. You have to have it running rough at idle, then have can of carb cleaner on ohand,

very lightly mist the t body as iff adding slightly more fuel. Curious as to whether when you do this misting you can keep idle steady, even and near normal RPM

Low idle is not vacuum leak

Check engine light coming on anymore?
Customer: replied 5 years ago.
I'm not at home to try at this time, but in a few later. How could I find a vacuum leak if there was one (or would it show in other engine functions besides the idle problem)? What should be the 'normal' rpm speed? And no, the check engine light has not come back on for quite awhile.
Expert:  Randall C replied 5 years ago.
soory, you have missed what i wrote

I am saying rule out vacuum leak, vacuum leak on fule injected engines make idle high, not low and rough

I am thinking its running a little lean. try the spray thing like adding a slight bit more fuel. LMk when you can.

I am most likely going to be online most of day Friday
Customer: replied 5 years ago.
Okay, do you have a suggestion after that try, if it isn't the problem or only solves it partially?
Expert:  Randall C replied 5 years ago.
not yet. I have to work through steps to at least know if running rich, lean, or ignition problem

best when near car then we do some things. Its a guess otherwise. i am not thinking a short. I suspect lean but will know more after you do the mist test
Customer: replied 5 years ago.
After reading your suggestions, I tried the cleaner. When the mist was sprayed the engine revved up some, then faded back. I repeated process, but engine got worse, so I increased the spray so as to clean it out. The engine started getting worse and rough. The check engine light came on also, but I knew it was because the air flow assembly was off the fuel intake. (sure enough the comp. code was PO201 and since I'd already replaced/repaired all designated problems, I ignored/disconnected the battery for a few seconds until the light no longer came on. Curiously, after revving engine/fuel the performance smoothed out somewhat. In addition, the idle speed would stay around 800rpms, then 'flow' up to 1300-1500rpms and back down by itself. Obvioulsy the idle speed also changed with AC on/off and when in Drive compared to Park. Still, though in spite of the fluctuation in idle speed from time to time, it DID level off to around 900rpms and fairly smoothly. I hope that while overnight 'rest' it will still show improvement. I will await your instructions/advice. Thank you
Customer: replied 5 years ago.
Okay, days later the problem returns off/on. Its still improved, but not solved apparently. Sometimes (when cold) will naturally idle higher until warmed up. After driving, will sometimes maintain a high enough idle (750+ rpms)or sometimes go back to stalling. Doesn't make sense that it is an inconsistent problem if it is the actual mechanical situation(s)? I'll try ur suggestion again to spray the throttle body as it worked when you told me to try last time. Any other suggestions?
Expert:  Randall C replied 5 years ago.
not right now but,, you do have to do spray tests ahead of the sensor , not sensor off . I need to know what engine does with spray with everything hooked up and MAF sensor on

the computer will try all it can to compensate for sensor off
Customer: replied 5 years ago.
I'm not sure what procedure u refer to. spray what exactly? I thought u meant to spray above/near the open throttle body while idling (which caused the engine to rev up briefly, then return to speed). MAF sensor? where would that be and what is the process to test? Also u say 'hooked up', yet I have to remove the air chassy hose over the throttle ('carburetor'?) to spray, which naturally sets off the computer sensor noting a lack of vacuum.
Expert:  Randall C replied 5 years ago.
when the car acts up, I am asking you to gently mist some spray ahead of the MAf sensor. so,, into the air cleaner housing. I am trying to see if running lean or rich

I really am at a loss with this right now. So hard not being there

I am only tring to see if engine speeds up, stalls etc with some spray.Its acting up off/ on for you, so.. I am unsure which direction to go right this second

The original question was idle up down and stalling, at times way too low. this really always adds up to dirty throttle body. IAC? maybe but you did that i think

stalling? this is odd. try to mist when it tries to stall. Maybe running real lean.

then you mentioned rough running

Soo,, what is it doing now? low idle, runs rough? missing, how is it on road? where is idle? speed?
Customer: replied 5 years ago.
I replaced the MAF sensor as one of the 1st attempted solutions. When you say to spray into the housing, are you referring to the section by the air filter, or the section above the throttle (carburetor)? I've sprayed air flow cleaner spray into the sensor part before. I've sprayed the carb. cleaner spray over the throttle/carb and it sped up briefly. Also, what is 'IAC'? The thing is, why is it not consistent if it is a mechanical problem? Shouldn't the problem BE consistent and not come-and-go as it is now? When accelerating, the engine has no problem other than the transmission is not shifting to overdrive properly (separate problem--likely spring broken/stuck, as I've considered loose/broken 2nd or 3rd speed bands). I can rev up the engine giving it gas and it will pick up rpms w/out a problem. I did that thinking the line just needed to be cleared, but the only time there is trouble IS idling--and again, that's only some days yes, some days no (or some morning/afternoon and sometimes later that day). I haven't tried to spray more cleaner into the throttle again/yet as helped when you told me to before....only lasted a few days before problem returned. That's what is so puzzling.
Expert:  Randall C replied 5 years ago.
sorrym bad storms last night, internet in/out

Ok, I cant think its mechanical. You said spray/cleaning may? have helped some at one point
I am wondering if maybe we have a bad IAC ( idle air control valve)
Its mounted to the throttle body

It controls idle and , can get gummy/dirty inside and when you cleaned the throttle body, some cleaner may? have got into the IAC and helped some but still its sticking

You can try removing it, turning it over, cleaning the inside with cartb cleaner. This may do the trick
If careful, you should be able to reuse the gasket with little trouble

#6 is what it looks like

You can click HERE to upload some repair information in .pdf file

Customer: replied 5 years ago.
Thanks, but I thought I'd written in the past notes that I'd just replaced the IAC and that's when u told me to repeat the spray procedure including cleaning out the throttle. All that's done and we're back here still.
Expert:  Randall C replied 5 years ago.
the post is real long, Its changed several times. Its hard not being there. I am here to help but..

can you write one more time what exactly the car is doing, what happens and when?

I know you have done before but things have changed from time to time.You did not use the words IAC or idle air control so i had to offer that. Sorry

If I have to, I will seek another expert here to see if they have any input

Please only list the exact symptoms.

Customer: replied 5 years ago.
Some days the car will idle normal (avg 750 rpms) and run fine. Some days it will last like that all day w/no problems. Some days the idle will start high (cold engine) then later start fluctuating idle speeds to below 700rpms and decrease from there rapidly to stall. Re-starting engine continues problem to stall until I rev engine to keep it from dying, then steady idle for a few moments and return to stalling. During travel, when stopped the engine will, again sputter to a stall. (also will do a single 'spit' or 'shoot' like tiny 'backfire' from carb.) Then another day it might run fine for a while and start stalling again or stall all day. Then other days it won't have a problem again for a couple days or more, but repeats problem yet again.
Expert:  Randall C replied 5 years ago.
after each time it stals, does it restart real fast or do you have to crank some or hold pedal or etc?
Customer: replied 5 years ago.
sometimes it even restarts when I just barely crank the key, but mostly have to hold the key for the usual second or less, so yes it starts right away every time. I've also tried lightly pumping the peddle just enough when the engine goes down to the stall rpm of about 400 or less and the engine sputters to higher rpm and then idles until it stalls again. Sometimes I can rev up the engine for a short-term idle stability and proceed on trip. Then sometimes afterward it'll work okay for awhile. It's the inconsistency that puzzles me the most.
Expert:  Randall C replied 5 years ago.
its odd, does not sound like vacuum leak, still sounds like low fule pressur at times.

goes back to having it do this with hood open and looking at it. Once idel drops low, gently spray some cleaner into the air cleaner only, if idle picks back up and smooths out? I still feel like loss of pressure breifly.

vacuum leaks cause very high idle

you have done the parts related to idel control so I still have to back up to possible low pressure but only at times
Customer: replied 5 years ago.
I really appreciate your patience as you can imagine how little I'm starting to have. I will try the spraying the air cleaner (over the air filter?). If a loss of pressure, why inconsistent?---(again the question of electrical problem comes to mind, but I've 'jangled' lots of wires to correct/test with no changes. In the past, however; the car went 'crazy' when I tried to start it--the ignition clicked and the gauges simultaneously jumped to maximum while all lights, wipers, etc. went on for a sec then nothing AT ALL (no action from ignition/engine). I popped the hood, checked the battery cables, disconnected the negative and when nothing, disconnected the positive cable and jangled them. That resulted in return of lights and ignition to normal. That was an isolated incident however and has only had a similar incident of just a gauge malfunction w/out ignition problem (and both those were a couple months ago--not since).
Expert:  Randall C replied 5 years ago.
well, what happens if you unplug the IAC, will it hold an idle and not stumble and stall?
Customer: replied 5 years ago.
I haven't done that since I first tried to repair that symptom (I 'IAC' the same as air flow sensor?). I unplugged the wires and the engine died (as I thought it was supposed to do).
Expert:  Randall C replied 5 years ago.
no, the idle air control, valve. you said you chaged it. Should haev 2 wires to it. Mounted on the throttle body. Not the sensor in the air intake hose
Customer: replied 5 years ago.
OMG! Are you ('choke') saying I have to DIG back there again after this amateur spent too much time (8hrs) reaching and replacing it before??
I mean, oh well, if that's what it takes. Or is there an easy way to reach the wire connections from the top?
Expert:  Randall C replied 5 years ago.
i hoenstly do not remember. i thought it could be done from under side

I was only suggesting a test if possible to do. i am trying to rule out a short or wiring or IAc problem
Customer: replied 5 years ago.
I repaired/replaced the part from under the car as it is the only say I know to reach it, but so many other parts are in the way from underneath also, such that I had to feel my way around blindly (and why it took me so long). If it is what's necessary to FINALLY solve this ridiculously difficult mystery, then that's what I'm willing to do. The thing is that I don't mind a lot of trouble and reasonable expense IF the problem is SOLVED ("all's well, that ends well"), but I'm disgusted at how many things and expenses done with NO change what so ever!! (really....3 months of trying??).
Expert:  Randall C replied 5 years ago.
some reason that uidle drops. the IAc controls it, the computer controls the IAC, lets say a wire is rubbed through at some pint in the IAC circuit, then the IAC may not work at times and it stalls. Now,, the one test is to unplug it , if possible, just trying to see if it will hold an idle maybe ruling out some things
Customer: replied 5 years ago.
Okay, I sprayed the air filter portion and the idle barely went downward. I unplugged the IAC and there was NO difference in engine idle; plugged or unplugged. Of course, when Air Flow Sensor unplugged, the engine stalled. Also, I've noticed that when the engine idle decreases to stalling point, it will 'spit'/'shoot' like a mini-backfire at stall. What next?
Expert:  Randall C replied 5 years ago.
i think you are missing the tests as I was asking

I needed the IAc unplugged when the engine was stalling, then wanted left unplugged to see if it will no longer stall

the spray into air cleaner? i needed this done when its ready to stall to see if a light spray will kick up the idle speed some.

Low fuel pressure at stall and it could spit back as its stalling due to lean condition
Customer: replied 5 years ago.
I'm not sure what you mean. Unplugging AT stalling point is near impossible unless I waited underneath for between minutes to hours as the stalls are not consistent or predictable. Also, opening the air filter portion of assembly affects the engine performance automatically due to lack of vacuum (and again, the engine would not necessarily stall in a reasonable time period of waiting for it)? Now, in ref. to low fuel pressure (intermittently) and lean condition. What solution(s) are suggested for adjusting/correcting those issues if they are a problem?
Expert:  Randall C replied 5 years ago.
well, lifteing the air filter lid per say like you are taking air filter out and leaving everything else hooked up will not have bearing on how engine runs. unsure what you eman by that. It does not affect vacuum right at air filter.

Since the problem is not consistant? then maybe buy a cheap fuel pressure guage. Hook it up to test port on fuel rail. Let it run and when the idle starts to dip etc. look to see if pressure dropped. it cant drop more than say 2psi. Its a test that has not been done and one I really would do first in the shop so..I have been trying to work around the lack of this test
Customer: replied 5 years ago.
Okay, I know how to do that because I have a '98 Ford Mustang 6-cyl 3.8 that still won't start w/out starter fluid after replacing 2 fuel pumps, testing the injectors (of which NONE are getting a signal), and fuel pressure was OK. I'm STILL at a loss on that one unless the fact that there was no key and had to replace the key cylinder setting off the 'theft' light. BTW; I'd checked/unplugged the theft device and only thing to change was the theft light off. Back to Focus--AutoZone has a rental gauge I can get.
Expert:  Randall C replied 5 years ago.
best we do the test
Customer: replied 5 years ago.
Not gonna be this afternoon unless later. thanks so much for your patience and help.
Expert:  Randall C replied 5 years ago.
on/off each day. LMK