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Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 23821
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
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I am a service technician, self employed. This 01 grand

Customer Question

I am a service technician, self employed. This 01 grand prix, came to me with a miss." seems to run down the road OK but misses at low rpm. I checked it out (snap-on solus edge) and it comes up with #2 cyl miss below 2K rpm. above 2K it seems to run fine and the scan tool shows nothing. I have done the following- swapped plug,( the plug looks to me like it is running lean) swapped wire with another cyl. replaced the inj. checked, with noid light, the inj, pulse, visually saw the the fuel coming out of the inj. swapped the coil pack assy, with another one. checked compression. removed the rocker cover to make sure the valves were moving far enough. checked for a "bright blue" spark. The above tests were not necessarily done in the order mentioned. To let you know that you are not talking the the regular DIY mechanic, I have a collage degree in Auto Mech. I worked in a Ford garage 11 years (A tech status) and have been self employed for over 20 years and I have never had a car do this to me without something jumping out at me.
JA: Are you fixing your Grand Prix yourself? What have you tried so far?
Customer: Hi. This car is a '01 grand prix. I am a self employed service technician. This customer brought this car to me with a "low speed miss, seems to run OK at higher speed". I connected my snap-on "solus edge" to the car and found the #2 cyl has a miss at low rpm, below 2 K, above 2 K it shows no miss. I have done the following; (not necessarily in the order presented) swapped plug with another cyl, swapped plug wire, tested compression, replaced the inj. swapped coil pack w/ another car, removed the rocker cover to ck valve movement, ck inj pulse w/ noid light. visually ck fuel from inj. during cranking.
JA: Just to clarify, what are the exact lights you're talking about?
Customer: you don't know what a NOID light is?
JA: Anything else you want the mechanic to know before I connect you?
Customer: not sure what else to say
Submitted: 1 month ago.
Category: Ford
Expert:  Michael Solis replied 1 month ago.

Hey! My name is***** have over 13 years in the automotive industry. I have seen numerous vehicles come in with numerous different problems. Read your description, I mighty have other possibilities.

What is the fuel trim currently at when it misfires?

Have you smoked check for vacuum leaks? (did not see any mentioning of testing out the vacum system)

How does the throttle look? No carbon build up?

What about the egr ports? All clean?

No intake leaking?

How about the crank sensor, did you scope it? No glitches?

No cats clogged? did you test them?

TPS 5 v ref?

If you have any other questions, I will help to the best of my knowledge. If all test is good, then I will gladly opt out & let another tech try for I would then run out of possibilities.

Expert:  Michael Solis replied 1 month ago.

What is the fuel pressure koeo, when it misfires and when the engine drives fine

Customer: replied 1 month ago.
Don't mean to burst your bubble but I have OVER 30 years in the auto industry. Please don't patronize me. It is obvious to me that you will not be able to help me. Please refund my money
Expert:  Michael Solis replied 1 month ago.

So you checked all that? Did not see that in the description, was not trying to patronize you as well. I was just trying to help an experienced technician with knowledge, (sometimes A tech will overlook something, its happened to all of us experienced technicians). I will opt out & let someone else try, was only attempting to help you. Did not mean anything beside helping you, my apologies. I know you will be requesting your refund, (that is completely fine), but please look over what I have stated, for I have seen a lot of misfire caused by something like that. Please scope the cam/crank make sure its within time (which I am sure it will be, i've seen one tooth off timing cause a non misfiring vehicle to misfire on the ecm)

Expert:  kalamykid replied 1 month ago.

If you would like to talk to a real tech, let me know ans we can work together to see what is going on with your customers car.