2017 Grand Sport, supercharged with A&A, DMS breakout kit, MSD high performance plugs wires, Alky meth kit, mighty mouse catch can, American Racing headers and x-pipe. 8,000 miles

It starting hesitating and stuttering under light acceleration, to a point that one time I wasn't sure I was going to make it home. I had recently purchased 93 octane from a station I had never been to before, so I wondered about water in the fuel. I put some water remover in the tank and after driving for about 30 minutes it really started to run better. But it wasn't fixed.

The stutter under light acceleration was gone, but under hard acceleration it still existed. Not consistently. So I replaced all the spark plugs. Again, it ran even better. But still not fixed. Now you have to be over 5,000 rpms and it'll stutter about 65% of the time.

I have a local tuner guy looking at it, but other than confirming a few things that's not wrong with it, we haven't landed on the answer. I'm NOT getting a CEL during any of this. He said he's seeing a misfire on cylinder 5 at times so I'm wondering if it's a coil pack. He's going to swap two coil packs to see if the problem follows it but rain has slowed things down.

I'm wondering if any of you guys have some other ideas that we can entertain or test out. Thanks.

 

I had some stutter at lower rpms (but still 18.6psi) and I had to gap the plugs at .022 to clear it up. I chased the issue for a while because I felt .028 was good enough.

 

Good point. That makes sense and I didn't change the gap from the box which was .40. I'm not making a lot of boost, but this could be a viable issue. Hopefully tonight he can do a test run and confirm if the coil pack is an issue or not.

 

Thats too wide of a gap for boost. You are blowing out the spark.

 

Thanks. I'll be taking it down to somewhere around .28 and see how that does.

 

[QUOTE=TitanTn;1598870945]Thanks. I'll be taking it down to somewhere around .28 and see how that does.[/Q

Yes 40 is not good even at 6 lb of boost this c7 looks like it likes from 26 to 32 max that will wk better to what boost level you are at. Robert

 

the tuner didn't know about plug gap?

 

Yes he did. That was me. He's saying the same things that you guys have been saying.

 

Is your vette an A8 or M7?

 

Sorry. Tried to get all the stats in the first post and I forgot that one. M7

 

Did you ever track down the issue? My car is doing the same thing. AA Si trim. Longtubes, X pipe, MSD wires. About 4-5k miles of being supercharged

 

It was either a combination of things, or one thing which solution was masked by applying multiple solutions. So I'm not sure which it was, but my problem has been resolved and here's what I did:

- recapped plugs and made sure all boots were firmly connected
- my tuner adjusted some fuel settings

Regapping might have helped, but I am suspicious of a plug boot not being secure. Most of them you can feel the "click" when the boot is fully secure. But not on all. With difficult access on the passenger side it's frustrating to not have clarity about the boots being securely attached. So in the back of my mind I wonder if it was simply a plug wire not being fully connected. But it all works now.