I have a 1990 Dodge Grand Caravan with about 130,000 Miles on it. It has Chrysler's 3.3L V6 engine. Recently, I've had an issue with it idling. What happens is that the idle will drop to about 300 RPM for a second, then it will shoot up to about 1000 RPM, then it will fall to the normal 600 RPM for about a second, and repeat. A few times it has outright stalled. Unfortunately, this is intermittant. It has only happened after the engine has sat a few hours (though it's only happened 4 times or so, so it may be concidence) or it may be related to a cooler engine temp. When it's happened, hitting the gas to bring it up to about 3000 RPM, then letting it fall back to idle seems to fix it - the car will happily idle then. Anything above idle and the car runs fine. The idle is a BIT rough, but keep in mind it is 15 years old. No violent shaking or anything, but not perfectly smooth like a new car would be. I've used my scan tool (Actron CP9150) and no faults are being logged. The voltage on the TPS does change, but I haven't had the tool on it while the fault is actually occuring (what idiot put the connector under the hood! :-P ) This happened once about 2 months ago, and I asked around and was told to clean the throttle body. So we took off the throttle body, cleaned all the gunk out, put it back together and it didn't happen after that, so I assumed it was fixed. Then this started happening this afternoon. I also should note that we did change the timing chain a few days ago. I doubt it is related, as this did occur once before back in december (though the car wouldn't idle at all then, just started and died) but figure I should mention that. Any thoughts/suggestions/tests would be appreciated.
Thanks, Eric Kotz snipped-for-privacy@erickotz.com