Hey ya'll. I am stumped need some help. My truck threw a P0301 cylinder 1 misfire code. I replaced the coil and spark plugs no change. I switched wire to another cylinder to check the wire, still cylinder 1 misfire. Pressure on fuel rail is good. Intake pressure good. Good compression. What am I missing? It definitely has the misfire rough idle. What else could it be?

 

Did you ever find out what was causing this?

 

Hope this helps you out:

Possible Fixes

• If all ignition components (including the plug) check out, start looking for fuel system problems. Check the fuel pressure in the lines and check the injector for cylinder 1. An engine stethoscope can be handy here, as a functioning injector will make a distinct ticking sound as it opens and closes.
• In the event that the injector, fuel system and ignition system all check out, you could possibly have an internal engine problem. It might be time for a compression test and leakdown test, as the issue could be a burned valve, broken piston ring, broken valve spring or a timing chain that has skipped a tooth so the engine's ignition timing is off.

In many instances a P0301 code might be accompanied by other misfire codes or possibly codes related to the camshaft position sensor or crank position sensor; problems with these sensors can definitely mimic a P0301 code.