I have a 91 RS with a 305. Always starts, runs good sometimes and runs like crap others. After idling for 5-10 min it will start to 'roll' or 'surge'. When running rough if I push the gas it wants to die. After driving for a while and turning off for 20-30 min and restarting it is usually the worst. Wants to die until I work the gas pedal and finally get rpms up to 3000. I have replaced dist cap, ignition module, plug wires, checked plugs, oxygen sensor, checked vacuum lines, removed and cleaned egr valve, pcv valve. The check engine lite comes on occasionally and goes off after 1-2 min. Could it be the TBI, should I remove and clean? Has new fuel filter too.

 

Get the codes from the check engine light and go from there.

 

check to see if you have steady fuel pressure.

 

the engine code that I am getting now is 44.
wats the best way to check fuel pressure, should I rent a gauge?
when running rough the car reacts better if I push the gas hard as opposed to easing the pedal down.

 

i'm not sure if i correctly remember the codes off top my head but i think 44 is running lean. might be your fuel pump going south, you need to check your FP.
if you are renting a gauge be sure to get an adapter for the TBI vehicles as well, it doesn't have a stock schrader valve like the TPI/MPFI setups.