Idle problems...

[BoostinIT]

this has been comming up only when its hot out like today, anything above 80 or soo. the idle raises alot after driving car for about 15-20min. It idles at anywhere between 1200 and 1900rpm. Car has TMO Stage3 and has a rock solid 900 idle everyother day of the week, but when its hot, i cant get it to come back down. And another thing i noticed when i bought the car, the isc motor was unplugged, all my buddys said the idle should be all over the place, but its not. So i thought well the idle's high when its hot, maybe its that isc, plugged it in.. same thing.. unplugged it, started the car, idle was all over the place from 2000 to 900 rpms, common i guess when isc is unplugged. Have you heard of TMO tuning a chip to run without isc plugged in???

 

[karbon]

Here's my theory: ISC was unplugged because it causes an idle motor failure CEL. I had a bad isc for months and it only threw a CEL once, so it's not always a failure you can rely on the ECU to reliably report. It has to match the failure condition. My thought is that you have a bad ISC, and that the idle has been doing okay all along resulting from a combination of your TMO chip and whatever the BISS is set at. I would test the coils on the ISC as per the factory manual instructions (also on vfaq). I'm betting that it's bad. It's not good to idle without the isc to stabilize it, although in some conditions you can bandage it up and make it idle just fine without it.

 

[BoostinIT]

i think the motor still works cause, i have had it plugged in and the idle is rock solid, but the throttle response isnt there, like it is when it is unplugged. Oh yeah this might mean something.. the idle doesnt change right away, it takes a little while(id say 15min of driving) and i do have the timing adv. gauge and timing runs more advanced as idle gets higher... is that normal??