I hooked up a vacuum gauge to where the evap line goes into the cylinder 1 runner and vacuum held steady at 18inHg so I don't think it's an intake manifold leak.
Just for kicks, I pulled the TPS connector to force the car into open loop. With the AP I monitored the roughness, and in open loop there was absolutely no roughness. In closed loop the roughness would consistently count at idle. Since open loop ran smoothly, I can rule out the following: injectors, spark plugs, compression.
I'm left with either a bad sensor or an exhaust leak before the front O2 sensor?
How do I test the MAF/Front O2 before spending $$ on the parts?
Anyways, I have a fuel filter coming because it's long over due (went to the dealership and they said the fuel filter isn't a serviceable item so I never changed it). Maybe this will help....