I just got done porting my manifolds and when I put everything back together I kept getting leaks at the manifolds. This happened like 6 times so I took everything back apart and thought I finally had it fixed. Now, with my A/C ON, the car idles perfectly. But it I turn the A/C off, the idle jumps around and the engine becomes very shaky. I would guess its a vacuum leak because of the freakin manifolds, but what the hell does the A/C being on or off have to do with it?

 

did you replace all of your intake gaskets??? dont know about the a/c

 

Mine does the same thing it idles perfect with the a/c on, so yeah i would like to know too....

 

I answered this earlier in another thread- when you turn the A/C on, the ECU energizes the air bypass solenoid valve, which routes a bunch of air around the throttle plates to help support the idle with heavy loads on the engine. Unlike the BAC, which "cycles" on & off several times a second to adjust the idle air with precision, the air bypass solenoid is an "all or nothing" valve, i.e. open or closed. In any case, to the point- this is conjecture on my part, based on educated assumptions- once the ABPV is open, so much "extra" air is routed into the intake system, that any small vac leaks become insignificant in comparison...My theory, take it or leave it

 

Does one require the other? I know they are connected but do they require each other? I should just dump them.

 

That makes sense. I am pretty sure that I have a very small vacuum leak at my LIM, so you could be right Wayne

 

lose the ac

 

Thank you for the shitty response.

 

Yea, anywhere else I would but in the beautiful state of AZ we hit 112 today.