Back story. 96 4dr auto. Bought with 187k miles. Now has 205k. Recently I got a P0303, cleared the code and it came back 3 days later. Did compression test, engine hot, WOT.

 Cyl 1 - 160
 Cyl 2 - 165
 Cyl 3 - 160
 Cyl 4 - 145

 Oil and coolant is clean and full. Newer NGK plugs and wires. Feels low on power. Went up a 7% grade this weekend and floored I was able to hold 45mph. MPG is around 19/20 city+highway.

 Any common failures? Things I should check? I assume a burnt valve or rings (Doesn't smoke though). Whats normal compression numbers?

This is why you do wet & dry compression tests - 99% probability your question would have been answered there & then - now you gotta go back and do it all over again.

Standard 199 psi, lower limit 170 psi, max. difference 14.2 psi (these are from the 16v g16 engine as used on a 99, the 96 should be similar.

What you look for in a compression test is the variation in the numbers, especially between wet & dry - if the numbers jump on the wet test, it'll be the rings, and there's a good chance you'll see that jump on #1, #2 & #3 - that #4 is a little worrying - you might need to do a leak down test to get a better idea of where the problem lies - and yes, a head gasket is a possibility, even though the oil & coolant are clean.

A little on the puzzling side - a P0303 points to a misfire on #3, not #4, but #4 is the one with the low compression...

  The Tracker is currently taken apart. Intake and valve cover removed. I'll do a wet compression test tonight and check the numbers again.