i have an 87 GTA 5.7 and here recently its been running pretty rough. at startup it idles high but simmers down to around 1000-1200 rpm which seems a little high to me but not sure. i drive for a little while and it runs great but then i can feel it hesitate and the SES light comes on and it runs really rough. if i come to a light or a slow cruise (below 1500 rpm) then it almost automatically drops to around 400 rpm unless i give some throttle. if im stopped rpm surges a lot and sometimes stalls out but fires right back up and runs fine. then rinse and repeat til i get to my destination. im getting a code 33 for the MAP but i have no idea where to find the sensor on the car to replace it and see if thats the problem. a friend also said it could be the EGR valve and i also have no idea where to find it either. the motors all stock and ive only owned the car for a year and half. a year of that i was in Iraq so im no expert on the motor yet. just need some help. any would be much appreciated guys.

Aron

 

ok, so if you have an 87 then it wont have a MAP (maifold absolute pressure) instead you'll have a MAF (mass air flow) sensor. its locared between your air filter housing and your throttle body. hope this is of some help.