My 89 camaro rs has a 305 tbi and it is running ruff at idle and acts like it is missing while running at high way speeds. Another problem i am having is when i put the gas peddel to the floor it wants to run good for about 2 seconds and cut out and die, sometimes it will shut off and sometimes it will come back on after dieing. the last problem i have with it is when i hit the brakes to make a rapid stop it will stall out. I Have a timing light and have it timed dead center. I have put new plugs, rotor, wires, and cap on it and just replaced the throttle position sensor thinking this would fix it but with my luck it didnt. I need your help, i hate to see my camaro like this. im not shure if this could be a part of the problem but i have a 91 brain and 91 tbi on it.

 

Check Fuel pressure - from your description you have classic symptom of a dying fuel pump.

//RF