P0300 Buick - rendezvous

Question

I have 25 psi in my 2 cylinder on a 3.4 liter miss fire code p0300 what can cause this cylinder to have low compression none of the others have low compression except #2 I dont understand why

Answer 1

Hi there,

There can be several reasons for low compression. A sticky valve or broken valve spring, a bad lifter or broken compression rings. Usually if you add a cap full of oil through the spark plug hole and recheck the compression and it comes up some more, then it's a ring problem. If not, then it's a valve problem.