1999 GMC Suburban P0300 Code: Rough Idle After Intake Manifold Replacement
Hello, I'm having trouble with my 1999 GMC Suburban that's showing a P0300 random misfire code. I've already replaced the spark plugs, ignition coil, cap, and rotor, but the engine still runs roughly and feels fouled. Two weeks ago, I had the intake manifold gasket (upper and lower) replaced. Since then, the issue has persisted. Given that the intake was recently repaired, I suspect potential causes such as vacuum leaks, distributor timing issues, or fuel injector leaks into the intake plenum. I'm looking for expert advice on how to diagnose and fix this problem. Any insights would be greatly appreciated. Thanks, Erwin
First, you're in the wrong forum. Second, after an intake manifold replacement, common causes of a P0300 code include vacuum leaks, incorrect distributor timing, or fuel injector leaks into the plenum. I strongly recommend returning to the mechanic who performed the work to verify proper installation and check for these issues before attempting further repairs.