I have a 2017 Stingray with 31K miles. In August of 2018 my check engine light, CEL, flashed for about 2 minutes then cleared. I took it to my dealer and based on the code, the CEL flashed due to a misfire in cylinder 5. They were, however, unable to determine an exact cause but felt it was bad fuel. I use only brand-name 93-octane gas, primarily from Mobil. Flash forward to last Saturday (9/26), my CEL flashed again for about 2 minutes then cleared. I did not notice any change in the way the engine was running. Several hours later, I went out and got about 2 blocks from my house and the CEL flashed again then turned solid. I turned around and went straight home. Monday morning I took it directly to the dealer and the CEL was still on. So far they have not been able to determine a cause, but again suspect the fuel. They did check the plugs and wires, and I'm not sure what else. I opened a case with Chevrolet and they called me to get details. (UPDATE: This time all cylinders are misfiring, not just cyl 5.) They are supposed to call the dealer on Monday and call me back by Tuesday. The Chevrolet advisor did recommend that I pick up the car, which I did on Friday, and drive it to see if I encounter the same issue. It has been riding fine since.

Unfortunately, right now, the car is effectively useless to me for other than local driving. If I go out of town, and the CEL flashes again due to misfires, it could cause damage. And I could be left stranded who-knows-where.

Has anyone had a similar issue? Does anyone have any thoughts as to possible causes or any other steps to take to get this problem resolved?
Thanks all!

 

Please keep us posted on updates. Hard to believe it's fuel related other than if it was the #5 fuel injector or related wiring. Poor gas would affect all cylinders and not just #5 cylinder.

 

I would also be looking for a broken valve spring, seems that GM has had valve spring issues for a while now. I get the feeling now the valve springs on on the Low Bid list & quality is poor. Until the last few years, you never herd of a valve spring breaking, now seems to be getting kind of common, just look at the C8 valve spring issues.

 

If it was a broken valve spring a doubt the issue would come and go; I recently broke an intake valve spring on my Camaro LS3 engine (163,000 miles so no complaints) and the the car stayed in limp mode and was not subtle that there was an issue!

 

First off I find it hard to believe that the dealership couldn’t diagnose a cylinder specific misfire !!...it’s either fuel, ignition, or mechanical...is this a misfire you can actually feel ??...I don’t know if these engine suffer from carbon buildup on the valves as many GDI engines do...if they use an AFIT(Active Fuel Injector Tester) they should be able to see if it’s injector related...if they are knowledgeable in the use of a scope they could have nailed it down to something ignition related or mechanical if they are well versed using an in cylinder pressure transducer...for any cylinder specific misfire I always use an in cylinder pressure transducer...I can tell if it’s a sticking or leaky valve, or broken valve spring without having to do any engine disassembly...good luck !!

 

Same thing happened to me. I had a hairline crack in a spark plug.

 

Is this a manual car? My Z06 had an issue with 'phantom' misfires and I tried all the usual fixes - plugs, fuel, etc - and eventually we found out it was a faulty clutch pressure plate which was causing the crank angle sensor to detect the slipping load on the crank as misfires.

If you have the same issue it is not something harmless though as the engine will richen the mixture to 'correct' this, causing backfires and probably fouling your plugs in short order.

Do you have the CEL code pulled from the ECU memory?

 

I have an automatic; although there are times when I wish I had a manual! The code is P0300. So far the car has been driven about 150 miles since the light went out and no reappearance of the CEL. Chevrolet is supposed to call me back today. Thanks for your input!

 

Thanks for your input! They supposedly checked the plugs.

 

Thanks for the reply. Chevrolet is supposed to call me back today with an update. Fingers crossed!

 

Agreed. I'd think the CEL would be back on if that was the case. So far, it's been driven about 150 miles since the light went out and the CEL is still out!

 

The latest incident impacted all cylinders. Awaiting callback from Chevy today. Hopefully, they will have some good news for me as far as resolution.

 

If this is a random misfire with none actually felt you may just need a “crankshaft variation relearn” with a bi directional scan tool...takes about 2 minutes to accomplish !!

 

Thanks! I will mention this to the Chevy advisor when she calls me back today.

 

After headers and lower pulley install on my c7z I started getting a p0300. No issues, and the car runs fine just gets the random flashing light goes away. This whole time maybe all it needed was “crankshaft variation relearn” thanks for the info.

 

I had the same issue (Code P0308) during a track day in August. Quick code read by a friend at the track indicated a 'misfire Cylinder 8'. Found a dealer about an hour away to diagnose issue. They found Service Bulletin # 4745338 - which indicated that there was a bunch of 'bad' plug wires that made it's way into the engine builds for, I believe, some 2017 and 2018 model year Corvettes.
They replaced the plug wire, cleared the codes, cycled through a few times. Ran the car the next day on track with no issues - been fine since. Have your dealer check on that service bulletin - might be all you need.

 

My service invoice showed the internal GM bulletin # as 4745338. Didn't find this through a Google search online, but this is the same info as the bulletin:

https://www.carcomplaints.com/Chevro...pip5159c.shtml

hope this helps

 

Thanks! I'll pass this along to my Chevrolet advisor.