looking for some suggestions on working on the idle problem on my 2g 4g63. its got “idle surge” aka high idle that cycles (because the car is in idle mode and only will allow it to idle so high). i tested the ISC and all coils are good, movement of the plunger is good too. throttle body is clean and closing properly. could this be the TPS? i’m afraid to remove it, since its adjustable i don’t want to mess up the idle further. any and all help is appreciated.
Is this a MAF system? Have you checked for vacuum leaks?
get out an ohm meter and check the TPS for adjustment and of course function. Alot of times what happens is that even though the throttle body is closed and the idle switch is closed, the tps is out of adjustment saying the throttle is partway open. The ecu reads all this and then begins to dump fuel then remove it because it doesnt know what to do.
http://www.plymouthlaser.com/tps.htm this is for 1gs…2gs have the idle switch built in so you ignore a pin.
Like stenseltzim saind…Check for vacuum leaks. Throttle body orings are notorious. Check the biss screw as well.
If you dont have a boost leak tester if you can get the idle to hold steady for a bit spray a bit of starting fluid around the throttle body or any shakey spots in your intake pipes. If there are leaks then the engines rpm will rise for a moment
more info, this is a completely stock car. i’ve already checked the BISS, going to check the EGR valve when is dries up some. its definitely getting too much air at idle (even when not surging, it idles too high). also, during beginning of the idle issue, it would idle high, then i’d drive it, and it would then idle low (almost to the point of stalling). just the other day i had to jump it to bring it home (was sitting at work for a few weeks with a weak battery) and it idled fine for about a half hour in the driveway. i then shut if off and started it back up 20 minutes later to find the high idle with surge and it hasn’t gone away.
check the fiav or whatver its called too.