some times it will not idle below 3500 rpm and when driving its like the transmission goes in neutral have to shit to low to get car moving again but sometimes the car runs normal
engine will not idle below 3500 rpm sometimes on 1996 Pontiac Grand Am
Check your minimum air rate by looking inside your throttle body to make sure that it is not hanging up for some reason. The throttle blade should be closed with only about 1mm ( .040 " ) clearance with your foot off the throttle. Do you have a Check Engine Light On? This can help pin point any hidden cause. For example, a wire could be broken between your IAC or TPS and the computer. This means that the computer does not know how much idle command it is giving it or what the TPS reading is. A vacuum leak may be a cause, but most V6 Pontiacs have a Mass Air Flow Sensor and don't 'run away' with high rpms from an air leak. If you had a bad Coolant Temp Sensor, it could keep your idle very high. There should be a code for this. Let me know how these tests work out.