check engine light is on

marko2007 · Post by **marko2007** » 20 Sep 2009, 13:57

2007 volvo v50 t5 check engine light on. Pulled codes it said miss fired on cylinder 4 and 5. Dealer said change spark plugs. I changed them and reset codes. 1 week later, light came on again. Car has 60k and can't figure out!! Car is now running ruff when starting. Please help. Thankyou :

Post by **JDS60R** » 20 Sep 2009, 21:09

Marko,
Sounds like failed coils or a blown head gasket.

Swap the coils from cylinders 1 and 2 to 4 and 5. Then see if you get a code for misfire in 1 and 2 . If so - replace bad coils.
If no solution with that process then test the coolant for combustions gasses. If no combustion gasses in coolant then head gasket is ok.

I always test the combustion gasses first but swaping the coils is free so I listed it first.

Please let us know what it was .

marko2007 · Post by **marko2007** » 20 Sep 2009, 21:27

check engine light still on code 300 what should I do ? .