Fault Code P0305 on 2015 Chevrolet Silverado 1500 4.3L Engine: Misfire in Cylinder 5
My truck was running smoothly until one day, while stopped at a red light, it started running rough with the check engine light flashing. I've already replaced the spark plugs, ignition wires, distributor cap, rotor, and oxygen sensors. Despite these repairs, I'm still experiencing a misfire in cylinder 5. Given this pattern, could it be a faulty injector or fuel delivery issue? I'm looking for advice on diagnosing the root cause of the P0305 code on my 2015 Chevrolet Silverado 1500 with a 4.3L V6 engine.
Perform a fuel pressure test and monitor for any drop in pressure during a KOEO (Key On, Engine Off) cycle—look for a decrease of X psi within 5 minutes. Check the spark plug in cylinder 5: is it fouled? Look for signs such as wet, black, dry, or tan deposits. As a precaution, consider adding a fuel treatment product like SeaFoam or Techron to improve combustion efficiency.