A little back ground first. I have a 1991 CRX. 125k. Recently took it on a 1600 mi journey and since then, all hell has broken lose. During this trip I was going through 1qt of oil every 350mi and near the end of the trip, at idle the car felt like it had a dead cylinder (shuttering at idle) and noticeable loss in get up.

There's is ZERO smoke, tail pipe is dry and no noticeable leaks (although I haven't gotten it on the lift yet). I changed the valve cover gasket (oil was spilling into spark plug tubes), plugs and PVC valve. I also ran a compression check and here is what I got:

Cyl 1: 150PSI
Cyl 2: 151 PSI
Cyl 3: 65 PSI
Cyl 4: 149 PSI

Obviously cylinder 3 is a problem. I poured a capful of oil into it and tried again, this time producing 90 Psi. Telling me the rings are possibly bad. But I find this puzzling. I've never heard of just one cylinder having bad rings, and the symptoms didn't occur gradually like rings, but suddenly. Does this not sound more like a valve issue?

Any Input?


PS: ignore the grammatical error in the title

 

Thats not bad rings, more like burned exhaust valve or bent valve.

You will need a leakdown test to further isolate.