I have a 2012 LT sedan automatic 1.8L that has stalled on me at idle or coming to idle 3 times this year. Once was after sitting out in freezing weather in February at a stoplight 5-10 min after I started driving, so I chalked it up to the temperature, since it's lived in my garage since 2013 and is never typically exposed to the elements. But then it stalled as I pulled back into my garage after running some close-by errands in April during 70 degree weather. So I had a diagnostic that was inconclusive, and I had some maintenance done to attempt to resolve any potential issues back on 6/7. On 6/7 the spark plugs were replaced by my local mechanic, they also replaced the cam covers because they were leaking, decarbonized the engine, and did a fuel system flush...I guess that didn't fix it, as it stalled again 7/3 at a stoplight after driving 20 min. Every time it started right back up no problem.
Now the newest problem - on 7/11 I was driving for about 20 min, had been up to 75mph on the highway, and was back down to 45mph for a few miles, but then it lurched and shuddered, then shuddered any time I accelerated. I was able to pull over and it was fine upon restart, and has not done it in the last few days or on the way home. The road was very torn up so it was probably exaggerating the problem even more. But the whole car just was shaking if I accelerated. It WOULD accelerate, but just wasn't happy about it. I checked the oil level and it was at minimum, but I was on an incline and on 6/7 the oil level had been at the normal mid mark. I added a bit of oil at a gas station and then did an oil change when I got home.
I've also had weird issues with the tachometer just cutting out mid drive since February. Again all is well after a restart. Have also had some intermittent hard shifting (both up and down). The maintenance 6/7 seems to have fixed the rough idle upon start, but after the 7/3 stall, I went into a parking lot and it was not an even idle at all for whatever reason. I don't really know how to describe it other than it wasn't an even whir, but more like whirwhirwhirWHIRwhirwhirWHIRwhirwhirWHIR (sorry not sure how else to describe that - definitely no expert myself)
The shuddering is new, and hasn't happened since despite driving further than 20 min. My searching landed me on another post in the turbo forum and it's exactly like that. No idea if it's related to the stalling.
No codes. No lights. For any of this.
My mechanic was at a loss pre-shudder. Spent 20 min on the phone going over what could possibly be causing this. Debating taking it to the dealer (my dad is convinced they're the experts, but I've always viewed them as a rip-off ofc), or maybe just trading it in. But it's been tried and true so far and I'd like to keep it even if I get another car.
I'm the original owner and have been doing my own oil and filter changes since 2017. I had GM Major Guard and the dealer did all the service until 2018. I needed some trim replaced in 2019, but this is my first mechanical problem since the Major Guard expired. There were several smaller repairs under that warranty and I've had all the recalls addressed. This mechanic is someone my friend trusts 100% and he's seemed knowledgeable and fair so far. Unfortunately I've spent $1,650 between state inspection, maintenance and repairs since April, so this is getting pricy for a car worth ~$4k. Not sure where to go from here. Any help or thoughts appreciated.
Edit: Someone did try to siphon my fuel between 6/15-7/3. There were finger smudges on the door and drips down the side (which I'm paranoid about when I fill and am very careful). I didn't have a lower than normal mileage that tank so I think they failed / got caught mid-attempt maybe.
Recent maintenance summary (think I've got everything from the shop written down):
State inspection
Tire rotation
Brake adjustment
Flushed coolant system
Changed cabin air filter
Replaced spark plugs
Replaced cam covers (leaking)
Decarbonized the engine
Fuel system flush
Oil change (Dexos 5w30 full synth, AC Delco filter)
Now the newest problem - on 7/11 I was driving for about 20 min, had been up to 75mph on the highway, and was back down to 45mph for a few miles, but then it lurched and shuddered, then shuddered any time I accelerated. I was able to pull over and it was fine upon restart, and has not done it in the last few days or on the way home. The road was very torn up so it was probably exaggerating the problem even more. But the whole car just was shaking if I accelerated. It WOULD accelerate, but just wasn't happy about it. I checked the oil level and it was at minimum, but I was on an incline and on 6/7 the oil level had been at the normal mid mark. I added a bit of oil at a gas station and then did an oil change when I got home.
I've also had weird issues with the tachometer just cutting out mid drive since February. Again all is well after a restart. Have also had some intermittent hard shifting (both up and down). The maintenance 6/7 seems to have fixed the rough idle upon start, but after the 7/3 stall, I went into a parking lot and it was not an even idle at all for whatever reason. I don't really know how to describe it other than it wasn't an even whir, but more like whirwhirwhirWHIRwhirwhirWHIRwhirwhirWHIR (sorry not sure how else to describe that - definitely no expert myself)
The shuddering is new, and hasn't happened since despite driving further than 20 min. My searching landed me on another post in the turbo forum and it's exactly like that. No idea if it's related to the stalling.
No codes. No lights. For any of this.
My mechanic was at a loss pre-shudder. Spent 20 min on the phone going over what could possibly be causing this. Debating taking it to the dealer (my dad is convinced they're the experts, but I've always viewed them as a rip-off ofc), or maybe just trading it in. But it's been tried and true so far and I'd like to keep it even if I get another car.
I'm the original owner and have been doing my own oil and filter changes since 2017. I had GM Major Guard and the dealer did all the service until 2018. I needed some trim replaced in 2019, but this is my first mechanical problem since the Major Guard expired. There were several smaller repairs under that warranty and I've had all the recalls addressed. This mechanic is someone my friend trusts 100% and he's seemed knowledgeable and fair so far. Unfortunately I've spent $1,650 between state inspection, maintenance and repairs since April, so this is getting pricy for a car worth ~$4k. Not sure where to go from here. Any help or thoughts appreciated.
Edit: Someone did try to siphon my fuel between 6/15-7/3. There were finger smudges on the door and drips down the side (which I'm paranoid about when I fill and am very careful). I didn't have a lower than normal mileage that tank so I think they failed / got caught mid-attempt maybe.
Recent maintenance summary (think I've got everything from the shop written down):
State inspection
Tire rotation
Brake adjustment
Flushed coolant system
Changed cabin air filter
Replaced spark plugs
Replaced cam covers (leaking)
Decarbonized the engine
Fuel system flush
Oil change (Dexos 5w30 full synth, AC Delco filter)
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