Help with 305 Tune Port Injection

[Godlover]

This isn't a Trans Am Forum but there seems to be vast knowledge on this site. Since I bought my 91 Trans Am with a 305 Tune Port - it is hard to start after it sits for two days. If I pump the gas some it will eventually start - once it starts it seems good. Then - about two weeks ago it started to act like the fuel filter was plugged. So I replaced the filter and the MAT sensor. Seems to run better but still runs like it has bad gas. At a stop sign - I drop it into first (it is an auto) and drive it hard through the gears and it runs great. Any ideas?

[MikeWa]

Time to plug it into a scanner and see what is going on.

 

Mike

[ragtop69gs]

Could be dirty injectors, low fuel pressure, pressure bleed off while sitting, catalytic converter. Pumping the pedal doesn't do anything, there is no accelerator pump in a fuel injection system (even a TPI).

[Condor]

On my '89 TransAM 5.7TPI it turned out to be the fuel pump. It acted just like a clogged fuel filter. It was a PITA getting to it as the tank had to be dropped. Mine died about 40 miles outside of Las Vegas in the middle of no-where. Believe me you don't want that to happen.

[raybear71]

Sounds like a fuel pressure regulator is bad. Unplug the vacuum line to it and rev the engine and see if it leaks gas.