1997 Hyundai Accent with code P0302

I just purchased a 1997 Hyundai Accent SOHC 1.5 with 115,000 miles on it. I hooked up my OBDII scanner and got the code P0302, which is misfire on cylinder #2. Ok, i did the usual, i put new plugs and wires in it. I even replaced the #2 fuel injector, thinking that was it.....still i have a misfire. I can clear the code but after a few minutes of running it comes back. I tested the coils and they are fine. I even checked the new plug and switched them around still P0302. I have a rough idle, but at high speeds it goes away. I can rev the engine up to 4000 RPM's and it seems to go away. Does anyone have any suggestions? The compression seems fine, I checked the valves, just by removing valve cover and manually moving the cam to see if i had a stuck valve but they all moved like they are supposed to. Any help is and will be appriciated.

Thanks,
Troy

Next check the injector for that cylinder. Listen for clicking and put a finger on the injector to feel vibration. If possible swap that injector with another one on different cylinder. Also check injector resistance to be about 16ohms. It might be clogged or bad injector.

Ok i checked and moved around all fuel injectors, they are fine. I did a compression test, on cylinders 1,3 and 4 i got about 180-200 psi, on the #2 cylinder i barely got 28 psi. I tore the engine down took out the pistons and the number 2 piston rings look the same as all of the other piston rings. I have ordered new rings and bearings for the pistons and rods. I know compression is my problem... but all the rings on pistons 1-4 all look the same just by eye, i havent guaged the rings. Am i on the right track? I think i am. Also i am going to rework the head too.

Thanks, troy

Checked the valves?

Ok, thanks andywheelz, I figured out my problem, the number 2 exhaust valve is warped, not seating properly. I am going ahead and replacing the valve as well as the rings and bearings since i have the engine tore down to the block I just found the warped valve this morning, while i was cleaning them. I just have 1 more ? What would cause the valve to warp? Its only warped a little, but just enough to cause cylinder to loose compression.

Thanks,
Troy