I bought a 2002 Wrx wagon (all stock) with 63,000 miles last December. Everything was fine and dandy until I towed ~2000 lbs across the country with a UHaul last summer. I don’t know whether the towing was responsible, but a month later my check engine light went on for the first of many times.
P0303, misfire cylinder 3. When I took it to my mechanic they first told me I needed a manifold sensor and mass air flow sensor. That didn’t do the trick, and they found that cylinders 1 and 3 were at 70 psi, and the vacuum pressure was off and wavering. Spent about two grand getting the cylinders removed, remachined by a machinist, and replaced.
A month later, light back on. Reflashed the computer software. Another month later, light back on. The mechanics started to feel bad for me, and replaced spark plugs, cleaned fuel injectors, and changed the coils around for no charge.
Another month, another check engine light with misfire cylinder 3. This time they took it to the Subaru dealership, measured the compression in the cylinders to be 140, 140, 150, 160. They said it will continue to misfire occasionally (especially at lower temps) and said there is nothing else they could do except for replacing the engine. They recommended I continue driving it until the engine starts knocking loudly and I notice significant deterioration in performance, which they said could be 2 months or 2 yrs. They said it should be pretty safe to drive, and that I would clearly notice noise as the engine gradually dies on me.
I don’t feel particularly safe driving with the knowledge that my engine could go at any time. I look at the money I’ve dropped already as sunk costs, as I’d rather have my Wrx in like-new condition (it has 83,000 miles and is otherwise in great shape) for about 4 grand (if I go with a used engine) than just about any car on the road. If I can drop 4 grand on it and get 5 more solid years out of it, I would probably cut my losses and take that.
I’m really hoping to get some advice on this situation:
I’ve checked the forums, and it seems that the misfire cylinder 3 code is something that tons of people chase after, and few seem to fully resolve. I think my mechanics have tried everything mentioned in the forums. Is there anything else to seriously consider, considering my mechanic and the Subaru dealership are out of ideas? Should I take it somewhere else for another opinion?
As this seems to be somewhat common in the Wrx, as well as other high revving 4 cylinders, is it worth the risk getting another engine? I was thinking something between 50 and 80 thousand miles, going for about $2500 with another grand or a bit more for installation. Should I spend more to try to find a younger engine? What model years fit my ’02 Wrx?
Any advice would be hugely appreciated!