Okay kids, anyone seen this before?

1992 Tracker, 200K miles.  Running rough.  Dad drove the car probably 200 miles before I got there to do a tune up.

Compression test = 155, 0, 165, 165.  #2 cylinder nada, nil, zip.  Wet test on #2 brought it up 30# on 1st try, 10# 2nd try (30 seconds later), 0 3rd try (another 30 seconds later)

Pulled the head.  Cylinder walls had NO scratches (I was impressed for a 200K mile engine!!!!).  Rings hold a puddle of carb cleaner overnight (no leakage past rings).  with 0 compression, there should have been a dropped vlave or a hole in the piston.

Machine shop found nothing with the head.  Pressure test was OK (slight leakage on #3 and #4 valves, #2 was perfect they said.  No warpage.

i could not see anything wrong with the head gasket, but they don't always show when they leak.  But 0 compression caused by a head gasket??  There should have been some compression loss certainly, but ZERO?

Ideas?  Input?  I'm gonna try bolting it together with a new head gasket and check compression this weekend, but I'm totally mystified.....

Normally I would say you have a bent valve, but it sounds like the machine shop checked it out. Sounds like a real puzzler... I guess try the head gasket and cross your fingers!

That is a mystery all right. You seemed to have checked everything I would think of. Let us know what you find. Could the rockers be stuck holding a valve or two open?

did you adjust the valves? Mine was doing the same thing and the exhaust valve had tightened up to the point it wasn't closing all the way!!!

  I have seen a situation that was very similar to yours,and even though it would hold fluid,it was still a ring.It is much easier to hold the carb cleaner than compression.

update - it was the head gasket.
I'm really impressed with this little motor.  I've abused the hell out of it.  200k miles and the cylinder walls looked PERFECT.  not even a ridge.  parts for the whole jobs were less than an intake manifold gasket on a GM3.1L.  Took less time, too.