I have a 2003 Grand Am with a 4cyl auto - over the last several weeks the car has been running like chit, I parked it downtown ran into a meeting returned 15 minutes later it wouldnt start - seemed to be a fuel issue, called for a tow, went back out 45 minutes later and it started like new.

SES light came on P0171

car runs great if it sits for 1 hour - not 59 minutes.....if I attempt to start it before 1 hour I have to pump the crap out of the gas perdal to get it to start, then to keep it running same thing, after about 3 minutes it will drive normal again....BTW while it is trying to start during this process it often stops running with a 'thud' or 'clatter' very rough, once it starts good to go.

replaced fuel pump, cleaned MAF sensor, replaced fuel sending unit, fuel filter, plugs, changed service stations for gas....

nothing is working, I work downtown portland and have to move the car several times for my job, its a bitch to constantly deal with this - I have seen several folks talk about MAF, PCV, O2 - any advice would be appreciated.