p0303

[chase567]

Hello, i have a 2010 ranger with the 6 cylinder engine. the engine light has been on for the past year but has turned of 3-4 times for a day or two at a time. there a cylinder 3 misfire. i have changed coil pack, plugs, plug wires, injectors, injector harness, intake manifold gaskets, cam position sensor and checked for vac leek. i’ve also done 2 compression test and they came back good. I'm stumped at what this could be. any help is appreciated thank you.

 

[superj]

welcome!!

i cannot help because you covered everything i would check. maybe the plug wire is arcing to ground?

 

[Kira]

How do you read codes?
I ask because I'd like to know if it was a P0303 code each time.
A cheap code reader in the vehicle is good for verifying the code in the first place, clearing the code immediately and noting how long the code takes to return.
Too bad you didn't swap what parts you could from cyl. #3 to another location to possibly isolate the problem.

Maybe remove the valve cover and turn the engine by hand until cyl. #3 is at TDC of the compression stroke and inspect valve action?