Subaru Repair: 96 subaru legacy power loss, crank sensor, oil sludge

Question
Hi, I REALLY appreciate your taking the time to help me. This problem has stumped both myself and professional mechanics.I have a 96 legacy 2.2engine with the following symptoms: There is a loss of power under load - either when accelerating up a hill, or at about 40 mph - and I get the code for misfire in cyl 2 or 2 & 3. the short term fuel trim goes way up when this happens. I have checked fuel pressure. It has new wires and plugs, a new knock sensor ( in my hunting for the cause, it was found to be kaput.) Also tested manifold vacuum, indicated no blockage in exhaust, and did a compression test which turned out to be fine. I did replace the crank sensor - which was also recommended and it seemed to help but just for a short time and the problem came back. I replaced the timing belt ( a second time - since it has about 180,000 miles on the engine).If you can help me determine what the next step might be, I would be very grateful.


Answer
I have the answer, but you wont like it.1995 to 1998 Subaru 2.2l has a problem with the valve guides shifting.Usually the exhaust valve guides will "drop",his causes the valve under certain situations to hang up or stick open causing lack of compression as the valves will be open when they are supposed to be closed the lack of compression will cause a severe misfire and lack of power.The valve will eventually close and the vehicle will smooth out.

The diagnoses is as follows

Drop the exhaust down and inspect the exhaust valve guides, look for one or more that appear to be sitting lower than the rest ,and seeing how you have the cylinder # 2 pinpointed i would look at that one first.

Subaru had a problem on the earlier models with sticky valves from oil sludge build up in between the valve stem and guide causing the same symptom.The valve would momentarily stick open.This has caused techs who don't know the car fits to try and diagnose.As mechanical problems usually aren't intermittent but on a Subaru they can be ,when a valve sticks open intermittently.So if you don't see a dropped guide look to trying an oil flush, and change with quality synthetic oil and a additive such as lube guard,followed by a fuel induction service to try and get the valves to quit sticking

I hope this helps there is a lot of info here to digest but the fix is here

Justin
All Wheel Drive Auto