Any One Have This Issue?

[cayman]

I have had this issue even before putting the SC on. On occasion, when I push the clutch in when rolling up to a stop, the engine rpm will drop nearly to zero, then oscillate back and forth between 0 and normal idle rpm (650). It will finally settle down at the normal 650rpm and everything is fine. I've cleaned the IAC motor and housing, even replaced the IAC motor itself. I think it was Sean Roe that suggested unplugging the PCM for a few seconds and plugging it back in as a remedy, saying that some with similar issues claim the PCM gets a little "confused" and clearing it so that it can relearn takes care of it. I've done this and it does seem to fix the problem but eventually the problem comes back. It hasn't outright died on me yet put it has come very close. '98 RT with 14,000 on the clock. No codes set. Brand new battery. Stock O2 sensors. Outside temp. doesn't seem to matter. Car runs great and like I said before, idles fine after going through this little oscillating episode.

Anyone else have this?

 

[Tom F&L GoR]

When you cleaned the IAC, the only important part (for the engine) is the pencil tip on the plunger and the orifice it pokes into. Those are clean? (Just checking.)

 

[Steve 00RT/10]

I have had this issue even before putting the SC on. On occasion, when I push the clutch in when rolling up to a stop, the engine rpm will drop nearly to zero, then oscillate back and forth between 0 and normal idle rpm (650). It will finally settle down at the normal 650rpm and everything is fine. I've cleaned the IAC motor and housing, even replaced the IAC motor itself. I think it was Sean Roe that suggested unplugging the PCM for a few seconds and plugging it back in as a remedy, saying that some with similar issues claim the PCM gets a little "confused" and clearing it so that it can relearn takes care of it. I've done this and it does seem to fix the problem but eventually the problem comes back. It hasn't outright died on me yet put it has come very close. '98 RT with 14,000 on the clock. No codes set. Brand new battery. Stock O2 sensors. Outside temp. doesn't seem to matter. Car runs great and like I said before, idles fine after going through this little oscillating episode.

Anyone else have this?

Exact same problem here since the SC install last spring (54K on car then --no prior problem like this) after about 40 miles and while beginning to log. I first replaced the battery. I have cleaned the IAC and tried putting a piece of smaller diameter hose inside the hose to the air cleaner (The Wizard). Disconnecting the 3 PCM plugs does not entirely clear the brain....at least not for this problem. Disconneting the negative(by the PCM) and the 3 PCM plugs for a few minutes clears this fault on my car----temporarily. After clearing the brain, I also reset the TPS range. The car runs perfect for a start cycle or two. Then it's back to the same problem. Mine has stalled--several times. Strangely, a slight blip on the throttle at any time while slowing down to a stop immediately fixes the idle to normal. I blip before it drops off. Pushing the clutch in at any cruising speed does not initiate the drop.......it goes right to normal while coasting in a higher gear at highway speed. I've just learned to live with it after monkeying half of last summer.

I was going to try swapping IAC motors in the next couple weeks before fireup time as we have another Roe car that doesn't want to idle down. At any rate, I'd really like both of them to work right if possible.

Steve

 

[InjectTheVenom]

Could it be a jerky TPS sensor and/or wiring to it? I remember a number of threads with similar problem descriptions where this turned out to be the culprit.