Idle Problem (Vacuum Leak)

[lamner]

hi! i have a problem with my ca. after driving a bit harder last time (not overheated) the idle is really bad (~400rpm) and the engine would turn off if you dont open the throttle. at higher rpms everything is ok. i thought it could be a leak and actually i heard a leaking noise near the intake manifold while idling. if i open the throttle you can't hear it.i also sprayed some starter spary onto the intake manifold (near the aac) and it helped with idle - so there must be a vacuum leak anywhere.

all the hoses are looking good so i decided to clean the aac completely and put new gaskets in. today i finished work, everything leakproof, but car idles bad like before. there is still this leaking noise at idle which i cant locate exactly, it's coming from the intake manifold near/under the aac - do you think its a bad manifold gasket? is there any other part wich can cause a vacuum leak in this area? hoses are all in good condition..

thanks in advance
greets!

[float_6969]

Well a vac leak wouldn't make it idle low, but idle high. Regardless, I think you need to start spraying carb cleaner on all the gaskets and see if you can find the leak.

[lamner]

thanks for the quick reply! but thats not correct - it depends on the engine. on the ca with iac/aac a vacuum leak will mostly lower idle and also stall the engine. vac leaks will cause low/rough idle and stalling because the iac wouldn't be able to work right (because it can't control idle constantly when there is a leak somewhere) and that cause lean fuel/air ratio.

i wil try now to find the leaking spot with some brake cleaner or anything - i can even hear it..

[Buddyworm]

The adjuster screw on your AAC unit may have backed itself out a bit from the hard driving. Had that happen to me before.

[lamner]

The adjuster screw on your AAC unit may have backed itself out a bit from the hard driving. Had that happen to me before.

thanks for the advice, will look for that later. but i dont think thats the problem, because as i said there is this leaking noise at the intake manifold which wasn't there before, and before that ride everything was running great (aac..). i need to find that leaking spot, any ideas where it could be?^^

[float_6969]

just start spraying carb cleaner around until you hear the idle change, then you've found the leak.