2001 GMC Jimmy PO305 DTC: Rough Idle, Poor Fuel Economy and Exhaust Smell After Fuel Pump Replacement

Model: 2001 GMC Jimmy Fault Code: P0305 Posted: 2010-01-28 13:08

My 2001 GMC Jimmy with 162,000 miles and a 4-door 4WD configuration has recently developed a persistent engine misfire indicated by the PO305 diagnostic trouble code. The vehicle previously wouldn't start, so I replaced the fuel pump. Additional repairs included installing a new fuel filter and a fresh battery. Since then, the engine runs roughly, exhibits low idle speed, shows significantly reduced fuel efficiency, and emits a strong exhaust odor. The PO305 code is now consistently triggered. Despite these fixes, the underlying issue remains unresolved.