weird start up problem

[bassboy3313]

hey. i am having this weird start up problem. when i go out in the morning to start my car up for the first time or whenever its been sitting for awhile and is cold it does this weird thing. i turn the key and it starts. rpms go up to 1500 then drop down close to 0 and almost dies. then it goes up and then drops down. it will bounce up and down for a couple seconds slowly starting to level out. when it finds its steady idle its around 700 until the engine warms up, then its around 900.

anybody know why it does this back and forth thing right at start up?

[sx moneypit]

Sounds like you have an idle air control valve problem.You can try cleaning it and the throttle body and see what happens. Also be sure the coolant level is correct.If the coolant is low it will give the coolant temp sensor a false reading and cause an erratic idle.
Modified by sx moneypit at 10:50 AM 1/23/2010

[bassboy3313]

so even if the coolant temp gauge on the dash reads between 1/4 and just below 1/2 when warmed up, that could be causing an erratic idle?

[vancouverbc]

so even if the coolant temp gauge on the dash reads between 1/4 and just below 1/2 when warmed up, that could be causing an erratic idle?

there are two coolant sensors. one for ecu

[bassboy3313]

oh! never knew that. thanks!

[bassboy3313]

last night i went to start it and it started, but the rpms dropped to quick and it died. wouldnt start again, just cranked. this morning i went to start it again and it fired up, but before the rpms could drop and die i revved it up until the idle became constant. does this mean anything else?