p0300 code rough idle on my 1999 Jimmy

Question

My Jimmy was diagnosed with a P0300 code. Rough idle. I have a new distributor, new plugs and wires, new fuel pressure regulator. Vehicle starts fine and runs extremely well. Smooth and instant acceleration, no overheating, no stalling just a rough idle. The only thing I haven't done is replace the fuel injectors. I was trying to avoid the most expensive fix. Does anyone know if this is the only option that I have left. If that doesn't work I am at a loss at what to do next. Its a 1999 Jimmy with 187,000 miles but looks good and runs great (except for the rough idle).

Answer 1

The best way to resolve the rough idle is to do a diagnostic approach to the engine, such as a ignition analyzer,  If the rough idle was caused by a leaking fuel pressure regulator the oil would smell with raw fuel,  Using a ignition analyzer would help point to that particular cylinder that is causing the problem.