Any ideas here? on 3 mornings in the past week I got a 0304 code (#4 misfire) on startup. On both instances, it was cold outside ~32 degrees. Engine runs and started fine. Opened it up on the road each time and no evident misfires. I cleared the code each time to see how frequent it happens. Code doesn't appear again for a few days, but comes back, within a minute of start up.

Plugs are pretty new, coils are not, so I replaced number 4 since it was cheap. Did not resolve the issue.

Recently (last week) had timing belt service and an "update" done by the dealer on PCV valve, and a flapper on the intake. All work was done at the dealer. They recommended an "induction cleaning service" on my next service last time I was there because it does have some vibation especially at a cold start. They also claim there is a minor oil leak on a vacuum pump but I cannot find any leaks anywhere.

Vehicle has 105k miles on it. Anyone seen something similar? I'm torn beteen taking it back to the dealer and going somewhere else. If it's not related to what they did I'd rather pay someone else.


Thanks!