Q: Random misfire - 2004 Chevy Express 2500

asked by on October 23, 2016

I have this van it was park for about one year. Know that a misfire code p0300 and the light plush all the time. I have check plug, plug wires, injectors flushing. Compressor, coil check, vacuum leak check,pulse in the injector, spark on the plug, plug wire, all coil wires temp sensor changed, and yet the van is miss firing code 300,I steel have miss fire on one side, CV6. CV4 most of the time. when shifted to drive Cy8. Cy2. Also miss fire .only on one bank all the time. i hook it to scanner do snot show any other code. I check intake for leaking, it ok, I switch plugs, coils, injectors coil wires ignition wires, from one side to the other side. I have no lack. any help. Please . It has only 15560 km .

My car has 155680 miles.
My car has an automatic transmission.

Hello. Most of the time if you have a multiple cylinder misfire such as this, it is caused by a fuel system problem. If the fuel pressure is low, then this will occur. If the fuel pressure is fine, then I would also check the signal from the crank sensor as a failing crank sensor can cause this. If that is fine also then I would suspect that there is an electrical issue in the circuit on that one side of the engine. If you want to have this checked out, consider YourMechanic, as a certified technician can come to your home or office to diagnose the misfire and follow through with correct repairs.

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