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roy
roy, import/domestic specialest
Category: Ford
Satisfied Customers: 5153
Experience:  ASE master tech for 40 years
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2000 Ford E-150, 5.4 L, 166K miles, custom conversion van,

Customer Question

Hello. 2000 Ford E-150, 5.4 L, 166K miles, custom conversion van, original owner, better than average maintenance for 16 years.
Months ago, engine started hesitating/stumbling on right turns only, from stop to go. Less frequent to more frequent over time. Weeks ago, stalled for first time, and then a few times since. NOW DANGEROUS. Also now hesitating on straight starts from stops, not only on right turns.
My research so far suggests many potential causes, and most look to be beyond the reach of me and my tools, but I decided to check here first and maybe save a few thousand Ford dealer bucks?
One potentially related item (vacuum). Some months ago, lost control of the A/C vents. My online research found the problem, vacuum leaking somewhere, probably the "surge" tank, which is almost inaccessible. Followed a video on YOUTube how to bypass the tank and it worked! But now I wonder if it affected some other vacuum system that is causing my hesitation/stalling problem? Service Engine liight does NOT come on. Scan meter was used by a parts dealer and no problem codes were found.
Some possible causes I have read about are:
-dirty or bad mass air flow sensor
-dirty throttle body
-spark plugs, wires
-coils (replaced 3 or 4 already, but symptoms were totally different)
-idle air control valve
-vacuum leak
-intake air temperature sensor
-throttle position sensor
-low EGR flow
The trouble is, I do not have experience with modern engines and no specialized tools. I do not want to just start replacing or removing and cleaning parts "willy-nilly" which can be expensive, dangerous, frustrating and ineffective. Rather, I am hoping that an expert here can apply some probabilities to the possibilities to save me some time, effort and money, and guide me through a fix. This is our only vehicle so it cannot be out of service for long periods, but a short-term rental car would be OK for a while.
Summary of key points:
-hesitation/stumbling was limited to right turns only from stop to turn. was that way for months. very occasional to more often, but never always.
-recently began happening on straight ahead starts from stop.
-recently totally stalled in traffic a few times.
-no engine light, no codes, no other problems.
-otherwise starts fine, runs fine.
-over the years, have had various system flushes, fluid changes, injector cleanings, throttle body servicing, etc., all done by auto shops. regular maintenance, oil changes, etc., done regularly.
-uses 1 quart of oil every 750 miles. no smoking, but exhaust seems more noxious than normal.
-began using partial synthetic, then full synthetic oil many years ago, after passing 100k miles..
Thanks in advance for your attention to this.
HHD
Submitted: 9 months ago.
Category: Ford
Expert:  roy replied 9 months ago.

good afternoon my name is ***** ***** I will assist

the first thing I would check is the fuel pressure. trying to see if it stays constant when your issue happens.

as far as your list, egr is the only possible. the rest will not efect this condition without other symptoms

Roy

Customer: replied 9 months ago.
ok - how to check fuel pressure?
Expert:  roy replied 9 months ago.

you need a tester. if you dont have one, you can rent one at a parts store. there should be a valve on the fuel rail. hook it up and monitor the pressure and see where it stays

you may have to drive it with the dog house off to read the gauge. we are looking for the reading when the event happens

Roy

Roy

Customer: replied 9 months ago.
can you tell me where the fuel rail is? otherwise, i will try to find it with google. also, what is the tester called? fuel pressure gauge? thanks.
Expert:  roy replied 9 months ago.

on top of the motor. it runs above where the plugs and coils are located. if you remove the dog house, it will be exposed. look on the rail for the valve.

yes, it is a fuel pressure gauge

Roy

Customer: replied 9 months ago.
ok - more tomorrow!
Expert:  roy replied 9 months ago.

ok

please dont forget to rate me as it is the only way I get paid for my efforts

Roy

Customer: replied 9 months ago.
i have used this system before so i know how it works. i think it is fair to make some progress before rating and paying. i will work on your suggestions this weekend. have a good one!
Expert:  roy replied 9 months ago.

ok

Customer: replied 9 months ago.
Roy - in thinking about your troubleshooting suggestion, it seems to me impractical. Is that what a Ford dealer mechanic would do? Somehow, I don't see him driving around town, for maybe a long time, with the doghouse off, a pressure gauge in place, waiting for a hesitation or stall to occur, which might take many days and nights, and then look at the gauge reading during the event. How could he drive and constantly watch the gauge at the same time? I guess it would take 2 mechanics, one to drive and one to watch the gauge. If I am missing something on this, please let me know, as I am disinclined to begin with this approach. Thanks.
Expert:  roy replied 9 months ago.

it is exactly what a good tech will and does. you need information at the time of the problem.

it takes one person not 2.

Roy

Expert:  roy replied 9 months ago.

please dont forget to rate me as it is the only way I get paid for my efforts

Roy

Customer: replied 9 months ago.
OK - i will give it a try! weather here (Tampa) is supposed to be bad the next couple days. This might take some time, but it is my top priority as it is a dangerous situation. thanks!
Expert:  roy replied 9 months ago.

your welcome keep me updated

Roy

please dont forget to rate me as it is the only way I get paid for my efforts

Roy

Customer: replied 9 months ago.
Hi Roy. Sorry for my silence. To update you, I've spent some time educating myself on the particulars of doing the fuel pressure test. I borrowed a guage kit from Autozone, let it sit a few days, and then discovered it was for cylinder compression, so I have to try to exchange it. Like most people, there are many demands on my time, so I have to set priorities. But the engine stumbled once on me today, so I do want to work on it soon. More later.
Expert:  roy replied 9 months ago.

ok