236k miles. Both heads rebuilt around 180k after we got it for cheap (tbelt break). Engine was replaced by previous owner, history not known. Sudden onset of running bad. May or may not have been some winter joyriding. Wondering about oil starvation? Runs very rough, engine is shaking, stalling at idle. cylinder misfire codes are not new. Able to limp home.

At the end look for the cam wobble

Tried a few quick fixes but no major improvement. The timing belt was off one tooth on the pass side cam. Reset the timing and runs better but still shaking, low power and still stalls randomly. Oil puddling on ground underneath on pass side from tbelt cover between oil pump and oil filter. Replaced the cam seal but probably also cam seal leak.

CEL flashing intermittently, probably misfires. New Diamond coil  (existing diamond coil didn't look bad at all). No improvement. Changed plug wires to new NGK (from existing NGK). New NGK plugs. FR5AP-11. A bit of chunky carbon on one plug (either 1 or 3) and #4 was loose possibly causing low compression and shaking.

Now running with naked timing belt so everything is visible. Passenger side cam sprocket is backing off the cam! Able to turn the timing belt with a socket on the cam bolt, but it doesn't feel loose at all. Cam sprocket is wobbling while running. It likely partially backed off the keyway. So many questions. Did the cam sprocket rotate on the cam? I just don't see how this would be possible.

Cam oil seal is compromised and oil is puddling below the cam. Oil coating the belt and flinging around the engine bay. Is the cam itself out of round? This seems impossible. Maybe the cam journals are gouged out. Car is knocking. Bottom end problems?

Finally got the car on a trailer after sitting in a parking lot up in Michigan for a bit. Back in the garage. Just now checking compression after finding a new ride for the daughter, of course a Subaru.

Cylinder compression is good on 1, 2 and 4 (220, 205, 200) but ZERO on cyl 3. Plugs look ok, not oily.

Will pull the engine and check out the head. Probably the valves got grenaded on #3 or worse. Car hit a deer in 2024, needing a bunch of sheet metal replaced in the front. Tbelt cover was cracked. Wondering if the cam sprocket took an impact that was missed.

Could be a broken cam between 1 and 3.