Fintile

Ok so I have this new problem. My car starts and drives fine but every now and again I'll come across an issue right after i boost. The rpms will not drop back down to idle...they wil drop to like 2k-1,500 rpm and sit there. i try letting in the clutch in gear to drop but it still doesnt work it jumps right back up. ive even pulled over and checked my tps as well as my TB to see if maybe it was stuck and it wasnt. So Ill turn the car off then on again. it goes back to normal then again if I boost it sometimes goes back to doing that or just acts normal. now it never seams to happen too often during the day. usualy around dusk. I was told it might be the temp. sensor thinking the car is running too cold but im not sure.

187sks

It sounds like your IAC to me.

03AccentVA

I'm far from an expert (and most likely <u>not</u> right), but is it possible it could be the wastegate not bleeding enough air. My line of thought is if not it'd still be adding pressure but when you cut the engine the pressure on the wastegate would drop allowing it to "reset".

Feel free to tell me why I'm wrong, cause I'm trying to learn.

omeletduefromage

sounds like either your thermostat or your IAC. i would try the thermostat test first cause its cheaper. you can check it in your oven. i dont remember exactly how, havnt done it in a while.

187sks

You can heat a thermostat in a pan of water on the stovetop with a thermometer in the water to see when it opens.

Fintile

might be...wheres the IAC again?

187sks

It's towards the IM side of the throttle body on the forward side. Looks like 2 merged cylinders where it mates to the throttle body.

sharkrocket

huh.gif Good luck with that man. unsure.gif

DTN

It would not be the thermostat. It would be the coolant temperature sensor, next to the coolant temperature sender.

I had a problem similar to this one when I had my idle adjusted too LOW! The IAC would overcompensate and bring the idle way up. Get obd-ii monitoring on your car. You can get with Jay-M from Jay-M's gizmos on RDTiburon.com to get a badass obd-ii code/sensor reader which will hook up to your car's computer through the obd-ii port and receive all kinds of information.

You want your TPS set to around 13%. The computer takes care of the idle on our cars. The IAC regulates it. The Coolant temp sensor looks for certain heat requirements to be satisfied before dropping the idle down. The butterfly can be adjusted to a certain extent until the IAC looses control.

If your idle IS in fact that high, you will have a code. You need to get the code read. Again, Jay-M is a cool dude and can help you out. NAPA/Advanced/Auto Zone will read a code for free.

I've had alot of idle problems in the past. Remember, the computer will attempt to regulate the car to 800RPM or 850 with A/C on. These values are + or - 100 rpm.

DTN

Odd idle problems can be caused by the TPS if the car thinks you're trying to floor it. TPSs can go bad. Try wiggling it hard to see if it changes the idle. If it does, there's a problem with it.