I have a 2012 Sonic 1.4L with the 6-speed manual and 13.5k miles (stock, no tune or mods). Early in November when it started getting colder (I live in MN) my car started experiencing vibration and reduced power coupled with a flashing CEL and solid ESC/TC light. This would only happen for 10 seconds or so before returning to normal with the ESC light going out right away and the CEL also after about another 10 seconds. While it was happening backing off the throttle would stop the vibration but getting back on it would cause it to start again.
As the month went on it started happening with greater frequency and duration (I think the longest it happened was 20 seconds but I was not closely measuring) and the CEL eventually stayed on (solid after the vibration stopped). I also noticed that it usually happened after about 30 seconds to a minute of accelerating to highway speeds on the first highway leg of my commute, both to and from work (my commute is almost all highway (at around 60 MPH) with a small bit on city streets to get there both from my apartment and office).
I took it to the dealer and unfortunately they were unable to reproduce the problem. They read the CEL code which was for a misfire on cylinder 4. We agreed that the code matched the symptoms I was experiencing but they weren't sure what could be the cause (they did check the plug and it was clean). They said it might be fuel contamination (though they checked for it and couldn't find any) and that I should put some fresh gas in and bring it back if it happened again.
For a while it actually seemed to go away. However, the first week of this month we got our first real arctic freeze (highs in the low single digits and lows in the negative teens Fahrenheit) and the problem came back even stronger than before. Worse, it was starting to occur at times other than "accelerating to highway speeds while warming up". On the Friday before I took it in again it happened while I was accelerating out of an interchange between two freeways in the middle of my commute. Then on Sunday I had to get groceries and it was happening (weakly but definitely) during the fast-idle after starting it up when I was making my return trip from the store
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I took it back in last Monday and it is still in the shop. From what I understand they are still unable to reproduce the issue and because from my experience the car needs to be cold for it to reliably occur each time they try they need to wait a half day before they can try again. The last I heard from them (this afternoon) they are having a GM technician come and look at it in person as they can't find a cause and remote consultation has not helped.
Has anyone else experienced anything like this? I actually feel like my dealer (Suburban Chevrolet in Eden Prarie) is doing a pretty good job handling this, but if anyone else experienced anything like this I would like to be able to pass on any information that would help them diagnose and fix the issue. I'm in a rental that is being covered under my warranty so there's not a lot of time pressure but I'd still like to get back into my own (working) car as soon as I can, particularly with the holidays coming up and the travelling I will be doing.
Also, could this be related to my driving style? I am driving the car to maximize fuel economy (so far I am very pleased with the results, especially in the warmer months) which means (in part) aggressive up-shifting. I generally shift around 1.5k-1.7k RPM after 2nd gear and almost always no later than 2.1k unless I need the extra power (e.g. for passing or going up a steep hill). This also means that I am actively accelerating in 5th and 6th gears much more often than I would assume most other drivers are. I tried to communicate this to the service writer when I brought my car in but I'm not sure I got through.
As the month went on it started happening with greater frequency and duration (I think the longest it happened was 20 seconds but I was not closely measuring) and the CEL eventually stayed on (solid after the vibration stopped). I also noticed that it usually happened after about 30 seconds to a minute of accelerating to highway speeds on the first highway leg of my commute, both to and from work (my commute is almost all highway (at around 60 MPH) with a small bit on city streets to get there both from my apartment and office).
I took it to the dealer and unfortunately they were unable to reproduce the problem. They read the CEL code which was for a misfire on cylinder 4. We agreed that the code matched the symptoms I was experiencing but they weren't sure what could be the cause (they did check the plug and it was clean). They said it might be fuel contamination (though they checked for it and couldn't find any) and that I should put some fresh gas in and bring it back if it happened again.
For a while it actually seemed to go away. However, the first week of this month we got our first real arctic freeze (highs in the low single digits and lows in the negative teens Fahrenheit) and the problem came back even stronger than before. Worse, it was starting to occur at times other than "accelerating to highway speeds while warming up". On the Friday before I took it in again it happened while I was accelerating out of an interchange between two freeways in the middle of my commute. Then on Sunday I had to get groceries and it was happening (weakly but definitely) during the fast-idle after starting it up when I was making my return trip from the store
.I took it back in last Monday and it is still in the shop. From what I understand they are still unable to reproduce the issue and because from my experience the car needs to be cold for it to reliably occur each time they try they need to wait a half day before they can try again. The last I heard from them (this afternoon) they are having a GM technician come and look at it in person as they can't find a cause and remote consultation has not helped.
Has anyone else experienced anything like this? I actually feel like my dealer (Suburban Chevrolet in Eden Prarie) is doing a pretty good job handling this, but if anyone else experienced anything like this I would like to be able to pass on any information that would help them diagnose and fix the issue. I'm in a rental that is being covered under my warranty so there's not a lot of time pressure but I'd still like to get back into my own (working) car as soon as I can, particularly with the holidays coming up and the travelling I will be doing.
Also, could this be related to my driving style? I am driving the car to maximize fuel economy (so far I am very pleased with the results, especially in the warmer months) which means (in part) aggressive up-shifting. I generally shift around 1.5k-1.7k RPM after 2nd gear and almost always no later than 2.1k unless I need the extra power (e.g. for passing or going up a steep hill). This also means that I am actively accelerating in 5th and 6th gears much more often than I would assume most other drivers are. I tried to communicate this to the service writer when I brought my car in but I'm not sure I got through.
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