SteelCoyote

Bought the car, got a CEL on the way home for p0303 #3 Misfire

Replaced the plugs and coil packs, had dealer adjust valves (72k mi on car) and CEL went away for ~1.5 months/800 miles (I don't drive the S2k much)

CEL came back on Sunday night, P0303, Cylinder #3 Misfire

Cleared code, waiting for it to return.

Car is stock except for Berk Full Race System (on car when purchased) w/ TP and CEL Fix bung (which shouldn't set a #3 misfire anyway if it set it'd be o2 related).

Suggestions for #3 misfire after plugs and packs have been replaced and valves adjusted?

TYIA

cleenyc99

if all your saying is correct. could be the wiring for the coil or injector has an intermittent open. could be the injector its self. could be the compression or your pcm. your going to need someone who's good at diag to take a look

SteelCoyote

The dealer wasn't much help, but I think you're probably right. Too many possible causes for me to diag at this point on my own probably.

Slowcrash_101

What about injectors? Have you tried swapping them and see if the misfire moves with it? I've seen it a lot on s2k's lately, lots of clogged injectors causing misfires. Take a look at fuel trims, if it's constantly in the + range it means the system is adding fuel meaning you have a lean condition.

afzan

swap your #3 and #4 coils and swap your #2 and #3 injectors, then check if the misfire moves or stays the same

franky

Do a dry compression test follow by a wet test. The worst case would be bent valves.

Gotpepsi

I bet that injector is sticking, especially if you don't use the car that much and the problem is intermediate. I suggest you do a dry compression test (to ease your mind of any major repairs), then swap your #3 & #4 coils and swap your #2 and #3 injectors like afzan stated.

Its an easy job to swap injectors, if I remember correctly, you just unbolt the plastic protector on top, then the fuel rail (gas will spray out), disconnect the injectors (be careful with the fragile clips), and pop them out.

To swap the coils you just take off the top engine cover to expose the 4 coils, then there are two screws to each coil. Unscrew those and pull the coil out. Just make sure to mark them before you swap things around so you don't lose track of things.

If you do a compression test, make sure that all cylinders are within range, e.g., 210,215,210,215 and not 210,215,190,210.

Lastly, once you have the injectors out you don't have to replace them. Just get them professional cleaned and flow tested.

SteelCoyote

Thanks guys, if I get time this weekend I'll swap the injectors and coils and see if it moves or not.

Bent valves on a new (to me) car would really suck.