My '2000 Grand Am has an 2.4L engine and 78000 miles. Recently, the idle speeds, parking idle and driving idle, go higher from original 600 RPM to 1000 RPM. Also, at low speed coast (release gas pedal), it keeps higher speed and takes longer time to slow down. I measured resistance of air temperature sensor, it has a reading ( I don't know what is a normal number). What is prolem? Please help. Thanks. James Z
I have an 02 cavalier with a 2.4 that did the same thing. I also went down the road of Iat senor after reading forum about high idle. Approximate temp Vs resistance at 77 deg f 2796 ohm 68 deg f 3520 ohm and at 59 deg f 4450 ohms. My car it was the tps sensor that was giveing it the high idle. It was telling the computer that I was at 2% throtle when I was at idle. You will need to put it on a scan tool that has datastream to see what the sensors read when running. Also depending on the scanner some will give you a read out for the IAT but if it is still under the hood expect the temp to be higher than ambeaint air temp.