Bad IAC?
05-30-2007, 07:34 AM
#1
Bad IAC? Recently been having a problem with the throttle sticking when idling. It's not physically stuck, it feels more like the engine is pulling more vacuum than it should be and until the throttle "cracks" open, it sticks. It typically takes a decent bump on the gas pedal to get the throttle to open up, so to try and fix it, I backed the throttle position screw on the TB out just a bit. Now, the throttle doesn't stick, but the car idles at 900-1000rpm. There doesn't seem to be a happy position for a normal idle and a non-sticky throttle.
The car isn't throwing a code for one, but it had crossed my mind that the symptoms the car has could be indicative of a bad IAC, since it wouldn't be letting enough air in at idle, thus causing the excessive vacuum in the manifold that's keeping the throttle plate stuck closed.
I've tried resetting the ECU, and unplugging the TPS and IAC sensors, and turning the ignition to run (but not trying to start the car), then plugging the sensors back in (someone told me that would "clear" the sensors in the ECU, and reset them once they were plugged back in), but that didn't help either.
Stock TB, all the sensors on it are stock, and the car has about 67,800 miles on it.
The car isn't throwing a code for one, but it had crossed my mind that the symptoms the car has could be indicative of a bad IAC, since it wouldn't be letting enough air in at idle, thus causing the excessive vacuum in the manifold that's keeping the throttle plate stuck closed.
I've tried resetting the ECU, and unplugging the TPS and IAC sensors, and turning the ignition to run (but not trying to start the car), then plugging the sensors back in (someone told me that would "clear" the sensors in the ECU, and reset them once they were plugged back in), but that didn't help either.
Stock TB, all the sensors on it are stock, and the car has about 67,800 miles on it.
05-30-2007, 08:24 AM
#2
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It might just be build up around the TB blade. With the PCV system, that can happen. Opening up the set screw to the point where it idles too high means you've gone outside of the operating range of the IAC. In other words, it's closed all of the way to try and prevent a high idle and too much air is still getting into the motor. I'd take an hour to pull the throttle body, take off the sensors and give it a good cleaning. Also, check your throttle cable for any obstructions or anything that it may get hung up on. Put it all back together and then see how it is.
05-31-2007, 11:24 AM
#3
Tried cleaning the TB out, and set the throttle cable back to the normal position, and as well as idling at 1000rpm, it's still sticking.
It's definitely sticking due to vacuum in the manifold. I might pull the TB blade up just enough so that it doesn't stick, then reset the ECU and see if that helps.
It's definitely sticking due to vacuum in the manifold. I might pull the TB blade up just enough so that it doesn't stick, then reset the ECU and see if that helps.
05-31-2007, 03:04 PM
#4
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Originally Posted by Element
Tried cleaning the TB out, and set the throttle cable back to the normal position, and as well as idling at 1000rpm, it's still sticking.
It's definitely sticking due to vacuum in the manifold. I might pull the TB blade up just enough so that it doesn't stick, then reset the ECU and see if that helps.
It's definitely sticking due to vacuum in the manifold. I might pull the TB blade up just enough so that it doesn't stick, then reset the ECU and see if that helps.
