Intermittent Misfire on Acceleration - P0302 Code in 2000 Camry XLE V6
My 2000 Camry XLE V6 has been experiencing intermittent misfires during acceleration, confirmed by the presence of a P0302 engine diagnostic code. The issue began several months ago and initially appeared sporadic—sometimes resolving with a tank of Chevron fuel cleaner. After visiting the dealer, they replaced the fuel injector for cylinder #2, recommending also replacing injectors for cylinders #4 and #6 due to equal labor costs. However, at $175 per injector, I declined the full replacement (totaling $475), as it exceeded my budget. On the drive home from the dealer, my wife reported a recurrence of misfiring during acceleration, accompanied by a flashing check engine light and the return of the P0302 code. I returned to the dealership, where they replaced the spark plugs for cylinder #2 and swapped out the coils—though no symptoms were observed post-replacement. They reiterated that injectors #4 and #6 should be replaced, but offered no diagnostic evidence supporting this claim. The car has been running smoothly since then, which is reassuring. Originally, there was some rough idle at traffic lights, but the primary symptom was occasional bogging down during acceleration. Cleaning the air intake pathways or fuel system has been suggested in other forums, but given the intermittent nature of the issue, I suspect a wiring problem—possibly degraded insulation causing arcing under load. It's possible that relocating the coil during service moved it away from an existing short. My key question: How specific is the engine control unit (ECU) in detecting misfires? Could a faulty injector in another cylinder still trigger a P0302 code, even if the actual misfire originates elsewhere?
Have you ruled out a bad spark plug or vacuum leak as potential causes of the misfire?