So no one at the shop could figure this out all day. Not to say they cared or tried very much, but it is bugging me so I was keeping an eye on it to see if I can figure it out or learn something.
It's an LTZ with just under 5k miles, all stock. Complaint is a random misfire at idle, especially when cold. We duplicated it as an occasional ignition (type) miss, a big hit / stumble at idle from time to time. There was a general misfire (P0300) set, but the freeze frame shows it set at a higher rpm. After blaming it on bad gas and debating whether to put a new head on it, they are letting it go since "it went away after a hard test drive". Trouble is I checked it and the intermittent big miss at idle is still there. I would really like to learn what caused it, and also would prefer to avoid dissatisfied Cruze customers for the good of the product. I datalogged a few sessions and it seems like it likes to hit on #1, but not consistently. Before we go swapping plug positions and such it's not a clear hit (at this time) on a specific cylinder, and very inconsistent / intermittent.
My question is has anyone come across anything like this and what was the fix, or are you aware of a TSB / PI on this besides the highly unhelpful "gas quality" bulletin and "general misfire diagnosis" document.
I am not even working on the car but I care because it's a Cruze
I will do a cold start misfire graph tomorrow (yes I work this Sunday )