Every time i start my car on cold start the car never idles high. I've swapped 2 different iacv and still have the same problem. Now the car goes up to about 1500 and then just drops to normal idle immediately. Any one have any ideas? No vacuum leaks, proper voltage at connectors, proper ohm's and voltage at air regulator connector, only thing i haven't changed is the air regulator because it looks hard to get to.

Hey, what are you referring to when you mention air regulator? I don't recognize that term. Sorry.

MAF and TPS, along with the IACV are the main bits for engine idle. I suppose the O2 sensors could be part of it as well.

You checked for vacuum leaks and that was a good place to look. Did you spray some carb cleaner or what? I just recently had to reseet my idle and timing to pass smog. In the past, I had issues with idle and it was a vacuum leak in my hoses from PCV valve to the lower intake pipes. That's pretty low down in the engine area, so you'd have to spray like into the intake 'tunnel' area to get revs to change.

You do adjust idle at the screw on the IACV and you DO NOT adjust idle at the throttle body. Checking your timing during and after setting idle is a good idea. Are you adjusting on a completely warmed up car? Are you unplugging your TPS while adjusting idle?

You might want to check the ECU for codes and see if a sensor is giving bad information. I think you do that with a screw on the ECU and read the blinking lights. Let me know if you need a link to some instruction for that.

centralcoaster33 wrote:Hey, what are you referring to when you mention air regulator? I don't recognize that term. Sorry.

MAF and TPS, along with the IACV are the main bits for engine idle. I suppose the O2 sensors could be part of it as well.

You checked for vacuum leaks and that was a good place to look. Did you spray some carb cleaner or what? I just recently had to reseet my idle and timing to pass smog. In the past, I had issues with idle and it was a vacuum leak in my hoses from PCV valve to the lower intake pipes. That's pretty low down in the engine area, so you'd have to spray like into the intake 'tunnel' area to get revs to change.

You do adjust idle at the screw on the IACV and you DO NOT adjust idle at the throttle body. Checking your timing during and after setting idle is a good idea. Are you adjusting on a completely warmed up car? Are you unplugging your TPS while adjusting idle?

You might want to check the ECU for codes and see if a sensor is giving bad information. I think you do that with a screw on the ECU and read the blinking lights. Let me know if you need a link to some instruction for that.

TIming is spot on, maf is good, tps is set at 0.45 volts, iacv has been replaced 2 times now. O2 sensor was replaced 2 months ago. I did spray carb cleaner on all vacuum lines and pretty much all over the motor and there was no changed. No vacuum leaks.

I did adjust idle at the iacv and not the throttle body and yes i unplugged the tps while setting the idle. Motor is completely warmed up.

No check engine codes.

I just replaced the intake plenum today and changed the gasket and put another good air regulator i had on. Put everything back on and it seems to be doing the same thing. Im completely lost and dont know what i need to look at next.

You need to think about what the ECM sees that causes an engine to idle high on cold starts.

Coolant temperature

theres 2 ECT (Engine Coolant Temperature) sensors on the engine. One for gauge (single wire), the other for the ECM (two wires). I'm not sure the temp/resistance readings of the sensor, but if the sensor if off a certain way, the ECM could determine the engine is warm and won't idle up. You need to check the 2 wire sensor for correct resistance in regards to its temperature. The check will be explained in the FSM on this forum that's free for members.

wa-chiss wrote:You need to think about what the ECM sees that causes an engine to idle high on cold starts.

Coolant temperature

theres 2 ECT (Engine Coolant Temperature) sensors on the engine. One for gauge (single wire), the other for the ECM (two wires). I'm not sure the temp/resistance readings of the sensor, but if the sensor if off a certain way, the ECM could determine the engine is warm and won't idle up. You need to check the 2 wire sensor for correct resistance in regards to its temperature. The check will be explained in the FSM on this forum that's free for members.

I've replaced the connector for the cts and the sensor itself about a week ago....

What about the sensor? Have you tested it or the circuits from ECM to ECT sensor?

I dont see the problem with it not idling high, if you depned on a 240 for clod weather driving there is a bigger problem!