Pontiac Repair: ENGINE RUNS ROUGH, throttle body injection, oxygen sensor

Question
I have a 1991 grand am with a 2.5 4 tech,  it seems to be dumping a lot of fuel in the carb,  i replaced the injector,  and still dumps a lot of fuel and runs rough,  no codes,  i don't know were to check the fuel pressure or how much it needs to have    have any ideals????

Answer
Hi Kevin:
that engine doesn't have a pressure tap to put a gauge on it you need an adaptor to put it on near the filter it's a pain. That engine more than likely had between 9-14 psi. It's a throttle body injection system on it. does it billow black smoke out the tail pipe? or does it just run rough? If it's dumping fuel and it's been doing it long enough it should turn on a check engine light and then you would have some where to start with what ever code has set. You could have a sensor that is skewed high or low and telling the computer to run in a lot to the engine with out a scan tool your really just up a creek with out a padel. You need to see what's going on before you start throwing more parts at it. These old systems were not really complex and are pretty easy to fix if you have the right test equipment "scannner". One really easy thing to check on this engine is the grounds at the engine block on the transmission bolts. I have see a ground go bad or even break off on these and it throws off the oxygen sensor readings and make the car run really "rich"