2001 Tahoe 5.3L Engine Misfire P0300 - Catalytic Converters Drilled, Poor Fuel Economy and Hesitation
The catalytic converters on my 2001 Tahoe with a 5.3L engine were drilled when I purchased the vehicle. I'm currently receiving a P0300 diagnostic code, which is indicating a random misfire. This is causing noticeable hesitation, poor acceleration, and significantly reduced fuel efficiency. My Zurich ZR11 scanner shows red alerts for 'Cat', 'EVA', 'HTR', and 'O25'. I'm looking for guidance on where to start troubleshooting this issue with the engine performance and emissions system.
Check exhaust flow to ensure there is no restriction. Perform a back pressure test under load to measure psi; elevated readings may indicate a clogged or damaged exhaust system, which could be contributing to the P0300 code and engine performance issues.