Not sure what to think

[TboneMinister]

Over the Christmas/New Year holidays, my Sonic sat for a little over a week. When I drove it again, something strange happened. I let the engine warm up, as usual. When I went to get on the hwy, it pulled normally in 1st. Then, in 2nd, it lost power and started lugging/misfiring (I'm assuming) accompanied by a flashing CEL and Service Stabilitrak message/light. The engine picked back up and lights/messages went away. However, power hasn't seemed as aggressive since. No further lights/warnings, no rough idle - but acceleration isn't as quick and (maybe this is just my imagination) even the exhaust seems less aggressive.
There are other threads that mention the flashing CEL, Stabilitrak warning, and misfiring, but in those scenarios they don't seem to go away. I'll probably data log and have Trifecta review, but I thought I'd check here for ideas. Mods are listed in my signature.

 

[SourKandi]

Maybe Check to make sure there’s no moisture at your plugs (coil pack to boots on the plugs) Mine did all those things when it was raining super hard one day & because it was misfiring it went limp mode, I ended up replacing the entire coil pack instead of just getting boots it seemed mine had failed in the end.

 

[TboneMinister]

Maybe Check to make sure there’s no moisture at your plugs (coil pack to boots on the plugs) Mine did all those things when it was raining super hard one day & because it was misfiring it went limp mode, I ended up replacing the entire coil pack instead of just getting boots it seemed mine had failed in the end.

Hmm...we did have a couple of days of decently heavy rain. Not to mention south TX humidity. I would think that I would continue to get the CEL and Stabilitrak warnings for misfire, though...

 

[SourKandi]

The flashing CEL does indicate misfire, as opposed to a solid CEL; tho the cause for yours to have misfired might be different I suppose. And yeah, it’s weird that it just did it that one time. Was hoping maybe to give you something “easy” to look for

I can say that I had no indication of any issue with mine until bam! one plug boot was so corroded that coupled with the rain it just failed miserably. Up until then I never had any misfire or other issues. I ended up having 2 really green plugs and another on its way. It’s not difficult to get a look at them, just to be safe. Just make sure the boots are snug when you re install the rail.

 

[macdiesel]

The flashing CEL does indicate misfire, as opposed to a solid CEL; tho the cause for yours to have misfired might be different I suppose. And yeah, it’s weird that it just did it that one time. Was hoping maybe to give you something “easy” to look for

I can say that I had no indication of any issue with mine until bam! one plug boot was so corroded that coupled with the rain it just failed miserably. Up until then I never had any misfire or other issues. I ended up having 2 really green plugs and another on its way. It’s not difficult to get a look at them, just to be safe. Just make sure the boots are snug when you re install the rail.

Can just the boots/springs be replaced?

 

[TboneMinister]

Update: Not really sure what happened. Maybe I didn't let the engine warm up enough, maybe something settled in the bottom of the fuel tank, maybe it just didn't like sitting for so long, lol. No further issues since and the car has been running and accelerating as I'd expect for the last few days. Thanks for the suggestion, though!

 

[dannyg]

Cheap gas maybe? Sometimes turbos can be sensitive to that. Try a couple of tanks of Premium in a row (not just one) as an experiment. Just a thought.

 

[SourKandi]

Can just the boots/springs be replaced?

I believe you can buy them separate from the rail, but if you buy the rail it comes with them.

 

[TboneMinister]

Cheap gas maybe? Sometimes turbos can be sensitive to that. Try a couple of tanks of Premium in a row (not just one) as an experiment. Just a thought.

I always run premium, always from a busy gas station, always Exxon.