I recently installed a Boost/vacume gauge. It is a cheapie from ebay, SPI. I wasnt sure what kind I wanted so I bought this till I decide. Anyhow, I notice my vac reading at 9/10 on idle, I know it is supposed to read about 16 or better. The car idles great, smooth, runs just fine. My rpm at idle is right on the money, no fluctuation, unless I turn on the a/c, then it goes up just a bit. The car dosent smoke, or use coolant/oil. Going to try and hook up a quaility vac gauge just to see if the reading is different. Any suggestions what else to check until then? Think it is just the gauge? TIA, appreciate any insight here.

 

Do you have the gauge hooked to the manifold nipple?

How have you run the tubing through the firewall? Is it getting pinched at all?

It sounds like the gauge may just really be off.

 

You don't say weather 5spd or Auto, but fwiw 10-12 in hg is NORMAL for an AUTO idling in Drive.

 

Sorry, it is a 5sp. I will check on the pinched tubing, I hooked it up to the capped off nipple on the pass intake. I tapped the gauge and it read 11, I think the gauge is junk.