I have had my scan Guage 2 hooked up for about a month now, been reading fine everything's normal, out of nowhere today my car started feeling sluggish. Almost like I had the A/C on. Scan Guage is reading no vac at idle, and 26psi at 5k. No svc or eml lights. No codes. Any thoughts ?

 

Cat issues will cause your boost to rise, if it's clogged or just starting to clog, it won't throw any codes yet.

 

BLWN. BRUH. Stop knowing everything. lol

 

Lol... not nearly everything.... but you have to learn something after 12yrs and 200k+ miles.....

 

A clogged cat would cause problems, but does the Scangauge account for ambient barometrics? 26psi minus 14.7 is 11.3psi which is about normal for a stock car. Did you get any codes? That much of a deviance should've immediately tripped a CEL, especially because the stock MAP sensors can't read that high of pressure.

Was the 26 psi you got at 5k on accel or decel? Because these cars can pull 24-26 in HG of vacuum on overrun.

 

I was pulling 0 vac at idle, and boost as soon as I hit the gas, 5k on half throttle peaking at 28psi. Just scared me because the car acted super sluggish, and shouldn't be making that much boost lol unhooked the battery, and reset my scan guage, all is good

 

Shouldn't be seeing 0 vac at idle.

 

Sounds like you have something going on. Your motor will not run at 0 vac.....how would it suck air/fuel mixture into the motor? You should be seeing around 12-14 vac at idle.

 

The car will run at 0" HG. Naturally aspirated engines see 0" vac at WOT, and force inducted engines see 0" vac before transitioning to positive intake pressure. The fuel is being injected into the intake ports at pressure along with a slight scavenging effect of the valve opening.

 

Yes, you are correct....but i was talking about at idle. The motor will not idle at 0" vac.