2000 legacy a/t 131,000 mi popping comin from drivers side , check engine light flashing , code reader 3-4 misfire, shop says cam is damaged , new plugs, wires, ejectors cleaned, fuel filter,good coil

Edited April 6, 201213 yr by 86subaru

2000 legacy a/t 131,000 mi popping comin from drivers side , check engine light flashing , code reader 3-4 misfire, shop says cam is damaged , new plugs, wires, ejectors cleaned, fuel filter,good coil

 

 

maybe slipped cam timing - was the belt done at 105K? who did the work and what was replaced?

 

any wrecks, repairs, towing, mods done before this happened?

timing done at 100,000 mi no damage, mpg at 25 highway ,when you push on gas is when it pops alot

burnt exhaust valve?

i really cant add to this thread but as with all 2.5's ....id start with having the headgaskets checked..... veeerrrryyy common problem..... and your 2000 legacy should definitly be a 2.5.

 

not sure if this would cause a missfire but ya never know

are the exhaust valves easy to change

i really cant add to this thread but as with all 2.5's ....id start with having the headgaskets checked..... veeerrrryyy common problem..... and your 2000 legacy should definitly be a 2.5.

 

not sure if this would cause a missfire but ya never know

 

Unless they've blown internally like the EA25D (DOHC 2.5 from '97-'99), then they leak externally.

Only way to know if its an internal issue is to do a compression and leak down tests to verify. They are known for dropping exhaust valve guides which holds the exhaust valves open. Drop the exhaust manifold off, take a flash light and look inside the exhaust ports. the guides should only stick out of the heads about 1/8" or so. If they are out any further, then you've got a dropped guide and the heads has to be gone through. If you do one side, might as well do the other side while you're at it.

3 and 4 are on opposite sides so I have a hard time thinking its timing/valve related. New spark plugs and wires will go a long way. Get NGK or Subaru OE wires and plugs.

already did , but will look again

3-4 use the same coil if im not mistaken. each coil pack has 2 humps so i can assume 2 coils. One for 1-2 and the other for 3-4. It's possible the coil inside the pack has failed? I've seen coils seem to do fine they just dont put out enough voltage so at idle they work great but when revved the exess rpm and pressure blows out the weak spark since the coil cant put out enough spark. So many of these cars use the same pack they should be easy to snag at a local junkyard for cheap just for testing purposes. That would explain the misfire but the popping im not sure of unless the coil has come apart and is sparking inside the housing? far fetched theory but possible.

ok, already swapped coils , but my spare could be bad