need help asap please help

replaced maf , iat , fuel filter has plugs and wires about 3 months old car backfires sounds like through intake could be exhaust im not sure i have a 1992 oldsmobile eighty eight royalle it hesitates and feels like it dont want to go most of the time up hills etc even going on flat from a stop it hesitates feels like something is holding it back.. can someone please help me ive been spending all kinds of money getting this car to work and it still doesnt work.

thanks

jason

Did you replace the CAT yet? After thet try checking the EGR valve for worn diaphrams and carbon buildup.

i had them check it out and the cat isnt restricting it and they said everything with the exhaust is good and he has alot of exhaust pressure