Misfiring on cylinders 1 and 3. Throwing P0300, P0301 and P0303.

GHOST_RADER

MEMBER
2001 SUBARU IMPREZA
95,000 MILES

I have a 2001 subaru impressa outback. - I have checked the compression(good), fuel pressure to that side of the engine(good), injector pulse(good), spark(good) even swapped a new coil on to make sure(no change), pulled the injectors out and made sure they were spraying which they are. I have also checked the timing marks to make sure it hasnt jumped time and thats in as well. I am stumped.

1 Reply

KHLOW2008

MECHANIC
41,814 POSTS

Did you check for vacuum leaks, especially at the intake manifold?
Are the compression as good as 2 and 4?
When valve clearances are too tight, they can show good compression but while running, engine might misfire. I would suggest checking the valve clearances and adjust if necessary.