i have a 1992 camaro rs with 305 TBI, the car i picked up for $400 dollars, very clean but didn't start, i replaced plugs, wires, and the rotor and it started right up, i also replaced the fuel filter too, but now i am having problems with the car running, it has a hard time starting, when it does start it idles rough and feels like there is a vacum leak or a missfire, ive checked all the vacum hoses and gaskets around the throttle body and have found no leaks, when i drive the car it hesitates alot when giving it gas, and the check engine light will come on every once in awhile, and gives a lean mixture code, i have replaced the 02 sensor, injectors, map sensor, fuel pressure regulator, fuel filter again, throttle position sensor, and still no change, then if i drive it for a while and then shut it down and let it **** for a little bit, and then try and start the car again, the car will start but then dies right away, and i have to keep pushing the gas to keep it running, i have took it in to get it looked at and they said it was the EGR valve, bu ti have replaced that too and still no change, so there went a waste of $90 dollars for nothing, so if anyone has any ideas, that would be very helpful to me

thanks