So a while back i posted that i had an issue with my idle control.. since then i have replaced the tps, iacv, and the throttle body. the problem persisted, everytime i slowed down the car would stall. so i disconnected the brand new iacv and presto, no more stalling. but i dont want to leave it disconnected as this is not the answer, also sometimes out of no where the idle will drop and the check engine light will come on and rapidly shut off and the idle go back to normal. any ideas?

 

When was the last time you checked the coils? , a scanner would be very helpful or have them checked at the shop. a cheap and inexpensive way is to wait until tonight remove the coil cover and start your car. should you see any arcing at any of the coils you will know that the coil needs replacing.

 

Hey Jeremiah thanks for your response, yes i have checked the coils in the past. they were all functioning 100%.I will check tonight to see if they are arcing but i dont think thats the problem.

 

The intake boot can be very difficult to get a good seal on the throttle body (allowing unmeasured air) - check that. Also the oil cap in the cam cover can leak air; you may want to replace it.

 

I will check the boot, but what do you think about the car running well without the iacv connected? very odd dont you think roger?

 

You're not throwing a code? It has to be an air leak... Check the mounting of the IACV to be sure it isn't loose.

 

Is the car still running the original crank position sensor. It could be an intermittent failure of the sensor. When the ISCV is disconnected it may be left in a position that gives a higher than normal engine speed. This would make the engine more robust to an intermittent CPS failure.

 

What is the IACV?

 

IACV is idle air control valve. It is a small round black object located on the top of the throttle body. the iacv is mounted tight and brand new might i add. And i will change the cps, once you send me the new bracket XJR! And i will also check for air leaks. thanks guys.