Today was the first time that I've ever used my A/C since I had my
AutoMeter Vacuum Gauge installed. I immediately noticed that my gauge
was reading 3-5" hg LESS then it was when I turned if Off!!??
Am I correct in assuming that this means I have a vacuum leak
somewhere in the system? Or is this normal?
I also should let it be known that this does NOT happen when I just
use the heat. When I use the heater, the vacuum pretty much stays
steady. It's only with the A/C that it's dropping quite a bit.
I was thinking that it might just have something to do with the ECM
commanding a higher idle when the A/C is ON, and since higher RPMs
equals lower Vacuum, I thought that "might" be the case. But I would
guess that the commanded RPM by the ECM is the exact same for both the
Heat and the A/C...and like I already stated, the Heat makes no
Anyone know what's going on here? Is there specific hoses that could
be leaking that are used during A/C operation but NOT during Heater