I suspect that my brake booster is leaking air into the engine. I have re gasketed my engine and sprayed carb cleaner all over but my Idle Air Counts still will eventually go down to zero which according to the books could mean a vacuum leak. The IAC is new and is working. Just that once it gets warmed up it goes down to zero counts when it should be from 20 to 30 counts. I tried blowing into the booster hose and found that it stops the air going into it. However it is not so good at holding a vacuum. Should it be able to hold vacuum? I think so but can someone confirm it for me? TIA

 

Yes, your brake booster hose is supposed to hold vacuum. The power brakes in our thirdgens are vacuum assisted.

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Mike

'90 IROC-Z, 5-speed, ZZ4, G1 Trick Flows
Moderator SEThirdgen