I read that you should have 17-19 vac on a stock engine. I only have about 15. I can't find any hoses that are off, but I am having problems with the secondary boost. The primary boosts to 12 or 14. Derek Vanditmars site is ok, but doesn't tell how to fix anything. I know my vac is low, but not why or how to fix it. The car doesn't smoke or idle funny, and there is no fluctuation in the vac at idle. What's up?

 

you have 12-14 psi on primary with a stock engine?

 

Are you sure the boost gage is not off 2-3 pounds?

 

Yeah, I have 12-14 on primary, usually 12 sometimes spikes to 14, I et off if it goes there. I have a dp, mp, catback.

 

Is the idle between 700-750 RPM?

 

yeah I think around 800 and steady after it warms up

 

If engine compression is not low and the boost gage is accurate,I would check the hoses again.You mentioned secondary boost problems but did not explain.

 

I have not had the compression checked. Think it's ok for the dealer to do?