bought a 99 si with a b18c1 boosted swap and cannot figure out how to fix the idle problem. it idles from 1500 to 2000 and its annoying what can be the cause of that??? tps maybe or not enough fuel pressure. also when i go to hit vtec the check engine light comes on for a second, it also boggs out when the light is on...

 

Pull the CEL code.

Have you checked for a vacuum or intake air leak?

 

No cell no vac leak and no intake leak

 

Explain your certainty here^.

Also do this test: Remove the air intake and use your finger to cover the hole inside the throttle body leading to the IACV or FITV. Does covering one of these holes make the idle speed settle down?

 

If I were a betting man, I'd put money on a vacuum leak. It's bogging in vtec because it's leaning out and can't compensate for the un-metered air. Your CEL is probably a lean code.

 

Are you tuned on <CROME>? There's a known issue with this. I have this from time to time.