Chevy Astro PO300 Missfire at 142k Miles - Intake Gasket Replacement Still Shows Code

Model: Chevy Astro Fault Code: P0300 Posted: 2006-12-08 13:56

I'm back with an update. After replacing the intake gasket, I discovered a crack at cylinder #1. To provide context: I've already replaced the spark plug cap, rotor, plugs, wires, and injectors. The catalytic converter was also replaced. Compression tests showed normal readings, and a smoke test revealed no leaks. The EGR valve was cleaned and confirmed to operate freely. Despite these efforts, I still experience a misfire at cylinder #1 specifically when the engine exits open loop mode. This issue resolves when running at 2000 RPM. Currently, the only fault code displayed is PO300. I'm concerned this vehicle may be beyond repair, especially given its high mileage of 142k. Any additional troubleshooting tips or insights would be greatly appreciated.