stumbling idle

purpony · Nov 27, 2007

I have a 2.9 with 232,000 miles. Truck starts fine (sometimes with a rocker tick that goes away, and sometime no tick) Truck idles fine when cold. Driving the truck runs great. When i come to a stop though it seems like the idle will hang high a little and then fall rapidly to idle.... so far in 2 months when its been doing this it dies but most of the time it catches itself and stays running.... when it does die it starts right up fine.

When it is idling though once hot hit has a little stuble to it. I am going to put new plugs, wires, cap on it this weekend. Also the fuel filter was just replaced.

I was wondering.... would it be worth putting new fuel injectors in? they are the originals-

IMenriched · Nov 27, 2007

Clean your IAC 1st. others will chime in and tell ya that the injectors are the last resort...they just don't fail very often.

ususally it the IAC or the FPR that gives you these issues.
maybe the coolant temp sensor giving the false signal the one for the computor, not the dash

purpony · Nov 27, 2007

I also forgot to mention that lately the temp has not been in the normal area (on the very low(cold) side)

I was also planning on putting in a new t-stat and also a coolant temp sensor.

purpony · Jan 18, 2008

I put a new IAC on the truck from my mustang and it made a world of difference!!! .... there is still just a very small stumble at idle but its about 85% better then it was.

Im guessing FPR = Fuel Pressure Regulator???
If so thats what i was wondering about also. Where is this located on a 2.9?

Psychopete · Jan 18, 2008

purpony said:
I put a new IAC on the truck from my mustang and it made a world of difference!!! .... there is still just a very small stumble at idle but its about 85% better then it was.

Im guessing FPR = Fuel Pressure Regulator???
If so thats what i was wondering about also. Where is this located on a 2.9?

Yeah. It's the round cylinder on the fuel rail, on the back of it, near the firewall, it's on the driver's side of the upper intake. Also has a small vacuum line come out of it that goes to the upper intake, and has a fuel line attached to the other side.

The cold running problem could be a bad sending unit, bad gauge, stuck thermostat, bad wiring, etc. The stock gauge is everything but accurate..

You might clear your CM codes, run it for a little bit, pull codes again and see if that gets you any closer to resolving your idling problems. It could just be a matter of a cylinder w/ low compression, a partially clogged injector (bad fuel atomization), bad valve seals, worn cam lobe, etc.

Pete

stumbling idle

purpony

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IMenriched

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purpony

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Psychopete

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