idle problems...related to climate control?

[MaDDaDDaM]

When I put on automatic climate control, my engine will be running at normal idle speeds and then suddenly drop to like 500 and almost stall out. Then it seems like it will react by jumping up to 1000 and then settling back down to around 750 a moment later. Then the process will repeat about ever 20 seconds. Has anyone else delt with this problem before? What do I need to do to check for problems?

 

[projectSHO89]

MaDDaDDaM:
When I put on automatic climate control, my engine will be running at normal idle speeds and then suddenly drop to like 500 and almost stall out. Then it seems like it will react by jumping up to 1000 and then settling back down to around 750 a moment later. Then the process will repeat about ever 20 seconds. Has anyone else delt with this problem before? What do I need to do to check for problems?

Idle Air Control Valve (IAC).

Clean it, otherwise replace it.

Steve

 

[sdpatt]

You should first try the idle speed reset procedure. If that doesn't change the behavior, the IAC valve is likely not responding properly and will need to be replaced.