sydeburn

Car is in NYC (currently parked in Queens). Re: Seafoam treatment-- I guess it can't hurt anything. Or can it?

I did end up taking this to a Subaru service center. They diagnosed the problem as "massive carbon build-up on one side of the head" and said they'd need to re-build the head to guarantee the check-engine light will go away. So now the question is: who wants to buy a H6 Outback for cheap? I can't afford to pay the Subaru service center for these repairs, and I don't have a place to do the repairs myself. It's a 2001 LL Bean edition with no rust anywhere, 9/10 leather interior, 8/10 exterior (a few dings). 122k miles. Needs the check engine light addressed and front CV axles. Engine actually runs smooth. Transmission is smooth and shifts without problems. No fluid leaks. KBB private party value in fair condition is $6120. Asking $3500. Please PM me if interested. Or if anyone wants to direct me to a more proper place to post this (since it's now basically an ad), please let me know. Thanks again everyone for your input.

Plugs were replaced.

Ok, here’s the update: the mechanic had already swapped the coils-- he said that was the first thing he tried. Sorry I didn't know that before. The code went away, then he took it for a 4-mile drive and the same codes came back. Cylinders 1, 3 and 5 misfiring. There were no other codes. I mentioned the timing on that side only and said highly unlikely and not worth checking since the car is running smoothly. Below are the remaining possibilities I've culled from this and one other forum. Can any of these be ruled out, in your experience? And which are more likely than others? Remember that the engine is running smoothly and there are no other codes... some fluke battery weirdness? igniters? a crankshaft/camshaft position sensor that's not providing a consistent firing signal? O2 sensor? (assuming each side has its own) fuel injectors messed up due to undercarriage pressure wash? fuel pressure regulator? (assuming each side has its own) fuel pulsation damper? (assuming each side has its own) fuel pump?

No compression test, and I'm kinda kicking myself for not asking for it, since he had the plugs out. He didn't say there were any other codes, but I'll call in the morning to confirm and post here. Could the timing be off on one side if the the car is running smoothly?

I just bought a used 2001 Subaru Outback L.L.Bean, and the check-engine light is on due to misfiring in cylinders 1, 3, and 5 (right side only). I thought I was getting a pretty good deal even given the CEL risk, but the car is at the mechanic now and he is stumped and telling me I have to take it to a dealer service center. This is a 6 cylinder with a timing chain. Plugs were replaced and computer reset and the light came right back on. There are no spark plug wires, and I read that the coil packs rarely fail. The engine runs smoothly and seems to have power, but since I just bought the car used so I'm not sure how much power is normal. It has 122k miles. What could be causing misfires on one side of the engine only? Any ideas?