My truck idles fine, but when I turn on AC idle drops from 800 to 400?

 

Sounds like you have a bad Idle Up Control Valve. It should activate when the AC clutch engages. Shouldn't be too much to replace.

 

Thanks for the reply....anyone with a 2nd gen know where the Idle Up Control Valve is located

 

I know someone knows the anwser to this problem....

 

My idle goes down when the A/C is turned on too...kinda makes sense if you think about it with all that extra drain being put on the engine. I'm not sure that it goes down that drastically but pretty close if I remember right...its done it for so long I don't even pay attention to it anymore.

Fink

 

mine goes up 250 rpms, it's only supposed to go up like 100.. deff. not down though. good luck on finding the problem,.

 

This is kind of frustrating.....I can't even find anything about this in my Haynes manual.

 

Yes but mine drops so much it kicks the ac off when idling.

 

This may have some answers for you:

Idel Air Control Systems

Or maybe this:

Part 3

Good Luck.

 

I have a 1st Gen 4cyl that does the same thing. just had the engine rebuilt and hoped that would help....nope ....but I figured as much. have not had time to trace it....but am very interested in hearing what people say!

 

Yeah...I had a brainfart, mine actually goes UP...I don't know what I was thinking. Yeah it goes up about 100-150 RPM's...man, I must have been tired when I posted that.

Fink

 

Not sure, but I think it started to happen after HG replaced...it cools when driving...not at idle....something needs to be adjusted or replaced...I know nothing about AC.....I have a feeling I soon will....I am leaving at 3am in the morning for Iowa with AC half working....should be cool then and wife and kids will not complain until noon. Taking a labtop so if anyone has any info I will try and fix this at the next hotel stop....

 

My RPM actually decreases. Yes...It goes down! Almost to the point of stalling. I have to do somthing about it. Someday I wil have time to figure it out!

I hate the AC game......you know......Pull up to a stop light....game off....pull away....game on......Great on the highway.....terible in town with no 55 Air!