spark plugs.

When my car is at idle, my understanding is that intake pressure should read zero on the VAFC and vacuum should read -20. recently i noticed that intake pressure is at .2-.3 at idle and vacuum reads -18. The throttle gauge shows that there is no throttle. Any suggestions why i'm not getting correct readings? btw, no CEL codes.

spark plugs.

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fsp31

What rpm is your car idling at? When mine is at 600-700, manifold pressure is around -21 or so. However, my car acts a little strange when it's below freezing outside (a recent development as I just moved from east TX where it never freezes). The motor idles between 1100 and 1500 rpm's in these conditions for some reason, and I have noticed that manifold pressure is about -18.

I never could resolve the problem. Temps warmed up, and now my car behaves normally, but idle was pretty bad there for awhile.

spark plugs.

well the vac is around there, but a few weeks ago, it was at -20 and 0 intake pressure at 700 rpm idle. car ran perfect and smooth. this was consistant. suddenly it's not. the idle feels a little shakey and seeing numbers off from what i kno to be a norm scares me. if anyone has info, please help.

fsp31

Sounds pretty similar to what I experienced. Even resetting the ECU didn't work. However, after things warmed up a bit, I reset the ECU again and everything was fine. It certainly doesn't sound like an internal problem with the motor. I'd say at worst you may be looking at a problem with your IAC valve. I'm guessing the cold air made mine stick or something. These kinds of problems are such a pain...