Engine racing at start-up, hot or cold

[Craigclick]

Engine races to 3k on start-up; when cold drops to 1.2 after 5 sec, then to .7; when warm, drops to .7 after 5 sec. Breaks my heart.

TPS has been replaced. One solution is replacing the gasket on the IAC valve with one whose holes are only 1/4" in diameter. This makes for a rough idle and the engine has to come up to operating temp before putting it into gear, or the engine will die.

 

[RonD]

Except for the 3,000 which should be about 1,600 on start up it sounds normal.

Computer opens IAC valve all the way on startup, warm or cold, so higher RPM is expected.

Check throttle plate spring, could be loose allowing plate to open a bit, adding more air.
Or maybe someone has adjusted the throttle plate screw thinking it was an idle screw, so throttle plate is open too much.
Or did the "throttle cable mod" wrong and that is holding open the plate

 

[Craigclick]

Thanks Ron for the suggestions; neither applied so I bought a new IAC valve which took care of the problem.

 

[RonD]

Good work, thanks for posting the fix