454 ss high idle

[1990ss454]

Hello, My ss 454 1990 trucks motor has a high idle. makes something in the front rattle. aslo when i use the a/c even gets louder. how can i lower the idle. and what can the rattle be.

Thanks a lot

[lowflyer]

Hello, My ss 454 1990 trucks motor has a high idle. makes something in the front rattle. aslo when i use the a/c even gets louder. how can i lower the idle. and what can the rattle be.

Thanks a lot

 

<{POST_SNAPBACK}>

 

 

 

The rattle is most likely the A/C compressor clutch assy. Again without actually having the vehicle in front of me, its a "best guess." but thats where I would start looking.

 

As for the high idle, its either a sticking IAC valve or a vaccume leak. Check around the Throttle body base and the manifold/head mating area. It would be helpful if you could scan the PCM and watch the IAC count to see what the IAC is doing.

 

If you don't have access to a scanner, take the IAC out and give it a good cleaning with sensor safe throttle body cleaner. Make sure you clean the seat area in the throttle body as well. Don't be tempted to pull on the end of the IAC valve, as it might damage the inner gears.

 

Good luck.

[1990ss454]

Hello, Thanks for the reply. What is the IAC valve, and the PCM and watch the IAC count to see what the IAC is doing.???????????????????

 

thanks alot