If I drive my car hard it idles high like 1300. I can kill it and crank it back up and it idles normal. What is the deal ?? Can someone give me ideas..

 

ok I put a new iac on and coolant temp sensor and it still does it. Also it won't idle up in the mornings..

can someone help..

 

I had this probelm also, The only way to fix it is to burn a prom. I decreased my Idle gain from 5 to 3, and set my max IAC counts to 60 from 145. Now the motor is unable to Idle above 1000 rpm.

 

I shouldn't have to burn a prom if the engine is stock. Stock 350 and tbi ecm and harness from donor vehicle.

 

may I suggest that a small vaccum leak might cause this.

 

could be a faulty Oxygen Sensor. That would explain why it wont idle up when cold. The 02 sensor is what the computer reads when it is cold after it warms up, and the 02 sensor gets a certain reading, the computer runs the car off of the water temp.
So when you start cold, the 02 sensor is probably giving the computer the wrong signal to idle off of the water temp sensor, which would cause a "weak" idle.

If its not the 02 sensore, get a new chip, maybe the ECM is going haywire.