Ok I believe i have finally come up with a diagnosis. when checking the scan tool, i noticed the mass air flow was at arounf 400mg/s and didnt really change even under full throttle, and according to mitchell, it should be 275-300mg/s idle and 1000-1200 at 30mph wide open throttle. i suspect faulty mass air flow, 300 dollar sensor will get it this week to confirm fix.