Does it smell like it is running rich?
Are you using a K&N air filter? An oiled filter can play hell with a MAF even when it is new.
Did you replace both the upstream O2 and the one after the cat? Any exhaust leaks?
Check for vacuum leaks @ the hoses and Map.
What fuel pressure did you get with the engine off? Does the pressure bleed down?
Does the pressure fluctuate with the engine running?
I'd bet on a fluctuating pressure regulator or a leaking injector. Try some injector cleaner or have them professionally cleaned. I like chevron with techron.
Good luck and let us know. :)
Friday, March 16th, 2007 AT 10:51 AM