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My 96 F150 5.8 4×4 (trans E4OD) has been giving me some intermittent issues. Some days on start up it will idle around 2k until I put it in gear, and it goes into gear with a loud clunck. When driving, some days doesn't want to shift between 1-2 and won't shift until rpm's get up to 2000-2500 and I let my foot off the gas. Then goes the same through every other gear. Other days I start it up, she idles around 800-1000 and shifts like a dream. When it is shifting erratically, some times it accelerates without my foot on the gas. There is no method to the madness. I was able to pull some codes the other day. No CEL, just ABS light.
P1401 Differential Feedback Pressure EGR circuit high input.
P0402 Exhaust gas recirculation flow Excessive detected.
P0141 02 heater circuit bank 1 sensor 2.
Any idea on where to start?
Last edited by obs_problematic_ford_girl; Jan 26, 2023 at 10:16 AM.
Good job pulling your trouble codes. Those codes indicate your EGR valve is stuck open or your EGR vacuum valve is leaking slightly, but that's not causing your current problem.
Sounds like a common failing TPS. If you have a multi meter, the first thing you should do is check your Throttle position sensors for dead-spots in it's travel. If you find dead spots, replace it.
Good job pulling your trouble codes. Those codes indicate your EGR valve is stuck open or your EGR vacuum valve is leaking slightly, but that's not causing your current problem.
Sounds like a common failing TPS. If you have a multi meter, the first thing you should do is check your Throttle position sensors for dead-spots in it's travel. If you find dead spots, replace it.
Out of curiosity (I’m not super familiar with the vacuum systems) how is the differential pressure related to the EGR? Do you know where I can find a full vacuum diagram?
When obd2 was adopted, the manufactures wanted to know /how much/ exhaust gas was flowing into the intake manifold, as oppose to the original method of only watching the position of the valve.
This is done with the "Differential pressure feedback electronic sensor" (DPFE). By monitoring the difference In Pressure across a restriction, the computer can determine if exhaust gas is actually flowing into the intake manifold, or if you have a clogged tube or valve. Your computer is telling you that the sensor is reporting a pressure differential when it's not suppose to. Possibly a bad sensor, or a bad wire.
You didn't mention if these were active codes or stored codes, so this may have been a code set a month ago, or it may be happening right now.
When obd2 was adopted, the manufactures wanted to know /how much/ exhaust gas was flowing into the intake manifold, as oppose to the original method of only watching the position of the valve.
This is done with the "Differential pressure feedback electronic sensor" (DPFE). By monitoring the difference In Pressure across a restriction, the computer can determine if exhaust gas is actually flowing into the intake manifold, or if you have a clogged tube or valve. Your computer is telling you that the sensor is reporting a pressure differential when it's not suppose to. Possibly a bad sensor, or a bad wire.
You didn't mention if these were active codes or stored codes, so this may have been a code set a month ago, or it may be happening right now.
Thank you so much for that explanation. They were active codes, but my CEL wasn’t actually on. I got confused and thought it was actually referring to the front or rear differential. I appreciate all the help!
Thank you so much for that explanation. They were active codes, but my CEL wasn’t actually on. I got confused and thought it was actually referring to the front or rear differential. I appreciate all the help!
***Update***
Replaced the TPS about 3 days ago and still not having any issues. Thanks for the help.
Replaced the TPS about 3 days ago and still not having any issues. Thanks for the help.
The computer uses throttle position as well as other sensors to determine when to shift the transmission. Glad the sensor fixed the problem. Hopefully you replaced it with a Motorcraft TPS or you might be doing it again soon.
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