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P0308 Fault Diagnosis - 1998 Chevrolet Silverado 1500 5.0L 305cid

Model: 1998 Chevy 1500 305cid 5.0 Fault Code: P0308 Posted: 2007-03-26 15:57

I'm experiencing a P0308 diagnostic trouble code on my 1998 Chevrolet Silverado 1500 with a 5.0L 305cid engine. After replacing the intake manifold gasket, I also replaced the distributor cap, rotor, spark plugs, and ignition wires as part of the maintenance process. The truck ran smoothly for about 10 minutes before I turned it off. Upon restarting, it began idling roughly and triggered a P0308 code. I tested the #8 cylinder spark and confirmed it has good spark. However, the plug appears to be in better condition than the others—still showing visible plating, unlike the worn-out plugs on other cylinders. Given that no obvious wear is present on the #8 plug, I'm wondering if there could be an underlying issue such as a misfiring due to fuel delivery problems or ignition timing issues. Any suggestions for further troubleshooting?

Related fault codes
P0308
Comments (2)
Anonymous 2007-03-26 17:42

Make sure all fuel injectors are properly connected and not faulty. Check if the fuel pressure is dropping, especially after engine restarts. Verify there are no vacuum leaks around the new intake manifold gasket installation. Also, consider that aftermarket distributor caps can sometimes cause inconsistent spark—ensure the firing order is correctly set and that the ignition components are compatible with the original equipment manufacturer specifications.

Anonymous 2007-03-26 20:17

Thanks for the helpful input—I'll verify all these points including fuel injector connections, fuel pressure stability, vacuum integrity, and confirm the firing order before proceeding further.