Ok so I replaced the spark plugs a while back, I checked the gap etc and replaced with top recommended spark plugs.
About 6-months later the engine light came on with code for misfire in cylinder 1. Replaced spark plug, which had some carbon build up on it. About a week later the light came back on with same code.
replaced all valve cover gaskets including the coil seals too.
Same thing happened again.
Swapped coil 1 with coil 3 to see if that was the problem. Same code came up on same cylinder. Only this time it went away after a day or two, was off for 2-3 days and then came back on.

Am I correct in assuming that it could be a bad fuel injector based on the carbon build-up? That is going to be my next swap!


thanks in advance for any thoughts or suggestions.

 

Swap cylinder 1 fuel injector with cylinder 2. See is the misfire moves.

 

great thanks, I'll try that!

 

Burning oil or coolant?
another good thing to check is the valve adjustment

 

Doesn't appear to be burning oil, coolant also is good and clean.

I was gonna go with the valve clearance next but figured I'd try the easy stuff first before jumping into the big jobs.

 

I second the suggestion to check the valve lash. It’s not a huge job, but if you’re unfamiliar with it then it can seem like a big deal. Once you’ve done it a few times you’ll be able to do it in under a half hour start to finish.

 

fortunately I have done it before and am pretty quick at it.

 

Before digging deeper, check the compression