2000 Pontiac Montana - High Idle?

Question

I have a 2000 Pontiac Montana that is idling at a high RPM, sometimes. It's usually at .5 RPM when idling. However, sometimes when I start the van it is idling at 1.5 or 2 RPM. I have to shut it off and restart, sometimes more than once, in order for it to idle normally. Just this morning it was idling high and I drove for about a block and when I stopped and put the gear in park the idle shot up to 3 RPM. I shut it down and restarted, and then it idled fine. What can I do to fix it, besides taking it in to an expensive mechanic (I simply can't afford that option at this time). Thanks!

Answer 1

while the motor is cold. take yer radiator cap off, and make sure the system completely full of coolant. do this by starting the car while the cap is off and let it idle untill it reaches full opperating temp. this you will know this when you have warm or hot air comming from the defrost vent by the windsheild. (set heater control switches to hot temp, and defrost setting, fan on high) this indicates the thermostat has opened. you then can finnsh filling the coolant system if needed. sometimes when air in the system passes the water temp sensor (ussually in the intake manifold) the temp sensor reads a colder temp therefore raising the idle thinking it is cold outside. if this fixes the problem then you more than likely have a coolant leak to address. if not,  have autozone do a soft code reading on your data port and see if the throttle position sensor has triggered a soft code in which case you will need a new one. just buy an ac delco from them, not a dealer. and it should cure the problem if that soft code is set. it will read " TPS " on the code reader autozone will do that for free.

Answer 2

it,s probably the idle air control or the throttle position sensor.