I finally completed replacing all four Flap diaphragms for HVAC controls. All diaphragms had either pin hole leaks or big splits. I also had to replace the rubber manifold that connects to the Vacuum control solenoid because it too had a big split.

Both engine and transmission seem to be running and working better. Transmission up and down shifts seem crisper. Throttle control seems better too.

The car really seems to be running better than any other period in the 4 1/2 years I've owned her. Do vacuum leaks even in the dash area have a meaningful impact on performance or is the beer talking me into something?

Thanks

 

Yes, Beer can talk loudly sometimes!!

 

Damn, thought I was on to something. Time for a Gin & Tonic.

 

If a pin hole leak can make you lose 1 mpg, then yes, it does have a large effect. Any vacuum leak is a bad leak and needs to be fixed.

 

Maybe THAT's what was plaguing Mark's stroker, then.....

Nothing wrong with the placebo effect, hard work deserves some returns real or imagined.

I agree though, I think that the HVAC leaks can have a discernable effect- they are plumbed in with the trans vac line and can exacerbate whatever other leaks are going.