98 Ford Ranger 3.0L with P0302 and P0455 Codes: How to Diagnose Misfire and EVAP System Issues
I own a 1998 Ford Ranger 3.0L 2WD automatic with persistent diagnostic trouble codes P0302 (Cylinder 2 Misfire) and P0455 (EVAP System Leak Detected). I've already replaced the spark plugs, spark plug wires, and coil pack — all of which passed initial resistance tests. I also replaced the gas cap and two fuel hoses, but the issues persist. A friend suggested a faulty fuel injector as a possible cause. While I’ve read similar posts on this forum, I’m unsure whether it’s the catalytic converter or another component. The engine runs roughly only at low RPMs and idle. I'm seeking reliable troubleshooting steps to identify the root cause. Any advice or diagnostic tips would be greatly appreciated.
How was the coil pack tested? While some coil packs pass resistance tests, they can fail when heated — using a hair dryer or heat gun to simulate real-world operating conditions is a good method. Coil packs were common on older Ranger models, as were ignition modules and intake gasket leaks. I recommend swapping the fuel injector from another cylinder to see if the misfire moves; this would confirm whether it's a fuel injection issue. It’s unlikely that the catalytic converter is causing the P0302 or P0455 codes. Also check for vacuum leaks, which can trigger both misfires and EVAP system faults. A failed vapor management valve (VMV) or solenoid could also be responsible. Keep us posted with your progress — this will help others facing similar issues.