Tony 85

So I bought a 85 corvette c4 and long story short it started sputtering at acceleration, also has a very rough idle. It sounds absolutely awful. So I replaced all the plugs, the cap, the rotor, and the mafs and it stopped... about 150 miles later the problem is back. What is happening?

pacoW

Basic checks, fuel pressure, vacuum, spark plug wires, compression test, etc.

Tony 85

So I just replaced the fuel pump and the problem persists just a slightly higher idle

billschroeder5842

Check your coolant temperature sensor. If your engine thinks its cold, you could be getting a fuel dump and it maybe running rich.

aklim

So? The regulator could be problematic as could the injectors and even the pump could be causing issues. That or all of them could be fine and your spark is bad. Check spark and fuel first.