So I’ve had a 96 outback for about two years now and when I got it it had a code for the crank sensor but nothing else. Changed out the sensor and within a couple days started getting codes for a misfire on #4 cel flashing. Changed out the plugs wires and coil and it went away for probably 1000 miles. It’s strictly a toy for the gambler 500 so it took about a year to put on the 1000. Recently it came back but light would turn of after a few miles. Now it’s on solid and has flashed a couple times.  It had always idled a little rough and just being a toy I wasn’t too concerned about it. Anyway I have been working on trying to get it to run a little smoother over the last week. Cleaned every sensor I could. Checked for any vacuum leaks and didn’t find any. Basically everything that all the other threads and forums say about misfire codes. Finally did a compression test and discovered cylinder 4 was way lower than the other 3. 1 2 and 3 all 160–170 #4 was at 90. Put 5ml of oil in it and only took it up to just under 95 but being a horizontal engine I’m not sure if the wet test even does anything. Engine was warm but insted of pulling the plugs on the injectors I unplugged the pump and relieved the pressure that way. Also throttle wasn’t open. So I guess my first question is would that have worked or should I retest? It doesn’t burn a drop of oil and no smoke. No oil in water and no water in the oil. No evidence of bubbles when I started it with the radiator cap off. Am I correct to suspect a valve issue? Gonna pull the valve cover as soon as I get the chance and take a look at the camshaft to check for worn lobes. Just not sure what is going on and I’m definitely no mechanic. Just go by what I find in forums and on YouTube. Need some advice before I start tearing the head off 

Burnt exhaust valve. 100%. You won't find a thing under the valve cover so unless you plan on pulling the head don't even bother. Is the engine original? If so it has hydraulic buckets/lash adjusters. They can burn valves though.

GD

Edited March 25, 20197 yr by GeneralDisorder

Yeah that’s what I kinda was assuming. Yeah it’s the original engine as far as I know. Looks like I’ve got some work to do. Thanks