2.9L rough idle when cold

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Aug 25, 2005 | 08:40 PM

jdwitte

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2.9L rough idle when cold

87 ranger w/2.9 when the engine is cold it doesn't want to idle but once it warms up for about 5min or if you drive it down the road for about a 1/4 mile it will run fine. It seems to run rich when I start it because it lets out a puff of smoke as soon as it starts.

Aug 25, 2005 | 09:14 PM

TigerDan

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From: The hills of No. Calif.

Have you tried to pull the codes? That's where I'd start.

Aug 26, 2005 | 08:24 AM

jdwitte

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when I check the codes everything comes back clear but since it only does it when its cold it may not have enough time to produce a code in the ECM.

Aug 26, 2005 | 10:08 AM

mrshorty

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From: UT

Maybe it doesn't have time to trigger a code, or maybe it's something outside of the EEC-IV system. You mention a puff of smoke at start up as if it has excess fuel, I think I would check for gasoline in the vacuum line to the fuel pressure regulator. A common failure of the FPR is to develop a leak in the diaphragm that allows excess fuel into the intake. You may have a small enough leak that it only shows up at start up, and once it gets the excess fuel cleared out, it can keep up.

Aug 26, 2005 | 11:43 PM

jdwitte

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I have already replaced the fuel filter & regulator a few months ago. Could a Ignition control module cause this?

Aug 27, 2005 | 08:38 AM

mrshorty

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From: UT

I suppose it's possible for the ICM to cause these symptoms, but it wouldn't be the usual symptoms of a bad TFI module. Have you tried cleaning the intake and IAC valve?