Mechanics

F150 POOR ENGINE IDLING

2002 Ford F-150

Engine Performance problem
2002 Ford F150 6 cyl Two Wheel Drive Automatic 105880 miles

Have 02 Ford F150 w/ 4.2L V6 and approx. 106K miles. Truck will not start/idle unless gas pedal is pressed. MIL is on and read a DTC of P1504. Replaced IAC valve with no change in performance. Sprayed some carb cleaner into the throtte body and truck finally idles although low and it still needed help starting. After the truck warms up, it idles low; around 500-650RPM. When under load (AC/Lights on) the engine loads down and idles real rough and surges. I've checked and rechecked the DTC and it always comes up with the same code. I don't want to do hit or miss troubleshooting. The original O2 sensors are installed and as best as I can remember had EGR valve replaced when the truck was under warranty. Have ran Seafoam through the vacuum system and added some to the gas. Until last week, truck ran great with the MIL coming on ocassionally but faults always cleared themselves. Prior to problem, truck was sitting for about 3 weeks. Any help would be greatly appreciated.
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Rjfoster1
October 6, 2008.




As you know P1504 is a Idle control valve malfunction. I doesn't say what is wrong. So with that does this truck have a mass air flow meter? IF so get some mass air flow cleaner and take it off and clean it. For future record do not use carb cleaner on the throttle body it is teflon coated and that will remove the coating and it will start to stick use throttle body cleaner ok. Let me know how this works.

Racefan966
Oct 6, 2008.
Thanks. Yes, I learned that today! Went by AutoZone to have them hook their code reader up cause I was concerned that the reader I was using was an older model that wasn't updated. It also read P1504 as well as P1507. With that when we checked under the hood for wiring issues we saw immediately (I hate this part!) That an animal (mouse, rat?) Had chewed one wire nearly in two and was working on the other on the IAC. I don't know how I managed to skip this step in the first place since I've been in maint all my life. Boy, did I feel stupid! Anyhow, temp fixed the wiring on the connector tonight; the truck started right up, idles fine, etc.
Thanks for the tip on the carb cleaner; I was a bit concerned that I messed up after reading some other blogs. I'll probably pull the throttlebody and MAF and give em' a good cleaning.
Thanks again!
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Tiny
Rjfoster1
Oct 7, 2008.
Your welcome and I am glad you got it running now. Any other question just ask.

Racefan966
Oct 8, 2008.

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