So this 2.5 sounds like the rod is about to drop, a bad metallic rattle which gets worse with rpm. weird thing is, only codes in memory are po301, 2, 3, and 4 (missfire, all 4 cylinders). The lady hasn't found the title yet, so I probably won't pick it up/tear down it till later next week but...whats the chance its not a rod? Could this be a bad idler or tensioner? The owner can't remember how if the CEL was on before the rattle, but it came on suddenly and she pulled over and had it towed. Its a '97 outback wagon, with 140,000 miles, no other known problems or whatnot. 5 speed, so not a cracked flexplate. I know...its probably the rod...

[...]Could this be a bad idler or tensioner?[...]

Sure, it could have a bad timing belt idler or tensioner, but given the misfire on all four and the noise, it might be accompanied with the timing having slipped several teeth on an interference engine.

That makes sense, bent valves for sure then. This is starting to look like a good home for that spare 2.2 I've got laying around. I'll check back once its ripped apart...pending that title thing...

So I pulled the timing covers off last nite and everything is lined up perfectly. I suppose the rod knock is bad enough to cause the misfire codes, since its got to play hell with the knock sensor. 2.2 swap...comin' up...