Check StabiliTrak light on, running rough and code P0300

Turns out it had a cracked piston in cylinder 1. It finally tore apart and went through the engine as we were driving it. It was covered under Chevrolet's power train warranty so they replaced her engine. Apparently there was quite a few of these cars that had this problem.

Hi,
Three weeks ago, I had my transmission failed and replaced with a brand new one. Five to ten days after that it began to produce an issue of after warming the car up to temp and then driving around for thirty to sixty minutes it would idle rough, and cause vibrations that you could feel all the way up into the driver seat at its worst. No check engine lights.

Things that were done to solve / narrow it down;
-oil changed.
-air filter changed.
-Mass Air Flow sensor cleaned with CNC Sensor Kleen.
-Cleaned the throttle body butterfly (TB is three months old).
-Ran 2 different brands of injector cleaner through it.
-Took out the one year old ACDelco platinum plugs that looked sooty around
the outer ring.
-Put the stock NGK iridium plugs in that came with the car.

Eventually brought it to the local dealer, who I told they had to warm the car up, drive for thirty to sixty minutes to produce the symptoms. They didno t want to do that because they need their techs during the day. So they looked at it anyway because I suggested it could be the PCV valve built into the valve cover being stuck open or something like that. They vacuum tested it and said its working fine and they could not find the problem. They suggested doing a clean of the injectors and such with their stronger cleaner as well as doing a bore clean. So they did all that, handed it back to me and said to put in my new plugs I mentioned I had but had not put in yet and that they highly doubt it would continue with the problem.

Ran some errands after work that day and the problem still occurred, no-change. Brought it back, they did not quite know what it could be, said to put my new plugs in; drive it for the weekend and see how it goes. If it still continues they would try to organize a ride along with a laptop plugged into it some evening. So I left and got one km down the road before something went wrong; Heavy misfiring, check engine light was flashing, stabilitrak turned off light came on. Limped it back and gave it to them. Called me the next day and said it was the coil pack and the number one cylinder plug had fouled. So gave them my new plugs and they replaced the coil pack.

Out for a drive again yesterday and the problem arises again after about forty five minutes. Pull up to a stop light and a vibration/rough idle begins at idle rpm of about 700 to 800 rpm until you get moving then its fine. You can also put it in park or neutral and it will still do it at this time too. If you start it from cold and warm it up and drive just a short period of time you will not have it occur and it will purr like a kitten but if you warm it up, drive it thirty to sixty minutes it begins. Still fighting with the dealership over it and they don't really seem like they know or wanna help. So taking a shot in the dark here on the kindness of strangers to help me out here. They have already have charged me $700.00 plus in repairs that have not fixed the problem. So please, if you might have an idea as to what the problem could be any information may aid my situation.

They used BG branded cleaner. They put a new coil pack on it yesterday. Stock air box and usually use esso, she'll, or petrol canada branded fuels at the manual suggested 87 octane. Tried higher octane to no difference.

Boots were also good condition before they changed it

Hello Adam did you have any luck getting this fixed?

Last night my car was idling louder and harder than usual and then a notification popped up saying something about my traction, I haven't driven it since, I don't know what to do

Yes, that was the summer past but yes. The garage would only road test it for 10-15 min despite me telling them it didn't occur until you got the car warm and drove it for an hour+. Even showed them video proof of the issue. They finally got the person who lived outside the city who works there to take it overnight. They got it to happen and. Immediately knew what it was they said. They didn't have the tramission mounts lined up correctly when replacing the transmission that failed at 76000km. Not my first time having them do this. Once before they fixed a commonly known warranty covered transmission leak on the bell housing and after I got it back it would clunk 1 out of 3 times you started it. When I went to show them it was one. Of those times it wouldn't until I went back outside and it did again. Went back in only to be told they didn't hear anything and thus they can see no problem. Complained enough to get a ride along with the service manager and before we got outside the garage door he picked up on it. Problem; they didn't tighten the bolts tight enough on the transmission mounts. So I've stopped using them since. Complained to Chevrolet directly and got nothing more then that's a shame that you won't be returning.

Thank you kindly Adam for info and swift response,

To be clear can you confirm the issue occurred in Neutral and in Park?

I’m experiencing very similar symptoms though does not present in Neutral or Park, only when the car comes to a stop with the brake applied; also if I apply handbrake and take my foot off the brake while stopped the issue disappears. I’ve been thinking some kind of vacuum issue(?).

Thanks heaps again
Joel

Ice had it happen with both. I thought mine was pc system but it wasn't. Get your transmission mounts checked.

When my car comes to a stop it pulses and shakes the entire car. The research I've done points to the MAF, MAP, or O2 sensors. I've had opinions thinking it was the MAF but not completely sure. Like to get a professional opinion.

I'm not exactly sure where those are located I'm a bit green when it comes to mechanical things quick learner just never taught

I have 3 codes showing p0106, p1101, and p0171

I disconnected the maf and it didn't run any differently than with it connected don't know if that could mean anything