'95 pickup with rough idle

wgonfan · Apr 28th, 2005, 10:47 PM

Hey there. my '95 pickup with 92k miles on the 4cyl has a rough (erratic) idle. During idle (more so when cold) the engine RPM will drop to about 500 or less, the rev back up to 1000 or 1100. Occiasionally it will go up to 1500 RPM & low enough to kill the engine. basically my idle runs like this - 1000 rpm for 30 secound, then drop to 500 rpm for 30 secounds, then peak up to 1200 rpm for 1 minute, back to 900 RPM for 3 minutes, drop to 500 rpm for 45 secounds & just goes on like that until I start driving. While driving the engine runs fine & does not lack power. The idel is erratic even if no acc are in use. The truck does not smoke or have any other symptoms.

What I have done --
I have used "seafoam" to clean the fuel system, change air filter & spark plugs. I have noticed that if I remove the wiring from the MAF (mass air flow) sensor it runs normal at idle, although you can smell the rich (or lean, I forget which is which) burn of the fuel. I would just leave the MAF sensor unplugged except that it causes the engine to flood while under accelaration.

Can anyone here point me towards a possible culprit?

Thanks,
TC

**88pathoffroad** · Apr 28th, 2005, 11:11 PM

Dirty MAF sensor, perhaps. Remove it and clean the heater wires inside very carefully with a Q-tip and some alcohol.