Stage 1 Intermittent cylinder 2 misfire

[Metro424]

Hey all 2016 Mk7 GTI with 72,000 miles. I went EQT stage 1 a couple thousand miles ago and am getting a misfire code that will pop up occasionally during a long WOT pull. EPC light will come on and cylinder 2 will be deactivated. Turning the car off and on clears the EPC light.
So far I’ve:
1. Replaced and correctly gapped spark plugs
2. Swapped coil packs around assuming cylinder 2 is the second from the left when looking from the front of the vehicle
3. Reflashed stage 1 just in case it was tune related

I’m still getting a misfire and trying to figure out what my next steps are. It looks like injectors would be the most likely next culprit and I was planning on doing a carbon cleaning while I have the intake manifold off to do injectors. I have owned the vehicle since new and have never done a carbon cleaning. Is there anything I can test for before I start replacing things?

 

[jimlloyd40]

How much knock?

 

[Metro424]

When I first logged knock it was averaging -0.75. I also changed which gas station I fill up at as well

 

[jimlloyd40]

Nothing to worry about at all.

 

[GTIfan99]

Nothing to worry about at all.

If he's getting EPC light and deactivation of the cylinder, then I say it's nothing to worry about.

 

[jimlloyd40]

If he's getting EPC light and deactivation of the cylinder, then I say it's nothing to worry about.

I mean that is a very small amount of knock. The OP should log it for EQT.

 

[Metro424]

Should I get a clean log when it doesn’t do it or a log when it does do? My car is higher mileage-ish

 

[jimlloyd40]

It would help EQT if you could log when it does it.

 

[Acadia18]

Time to do a compression test, cross your fingers, and hope for the best. Although if you've eliminated plugs and coils as the problem, the outlook isn't looking good.

 

[jimlloyd40]

Time to do a compression test, cross your fingers, and hope for the best. Although if you've eliminated plugs and coils as the problem, the outlook isn't looking good.

He only has 72,000 miles and very minor knock. And he just tuned it. The EPC light needs to be diagnosed.

 

[GTIfan99]

Should I get a clean log when it doesn’t do it or a log when it does do? My car is higher mileage-ish

I'd get both.

 

[Acadia18]

He only has 72,000 miles and very minor knock. And he just tuned it. The EPC light needs to be diagnosed.

You're right minor knock isn't an issue. But knock and misfires aren't the same thing. Misfires can cause engine knock, but not all engine knock is misfires. If he's getting misfires on a single cylinder, that is repeatable and causing an EPC, and has eliminated both spark plugs and coil pack as being the issue, that's not a good situation to be in. It usually indicates a far more serious problem.

 

[jimlloyd40]

View attachment 196790

You're right minor knock isn't an issue. But knock and misfires aren't the same thing. Misfires can cause engine knock, but not all engine knock is misfires. If he's getting misfires on a single cylinder, that is repeatable and causing an EPC, and has eliminated both spark plugs and coil pack as being the issue, that's not a good situation to be in. It usually indicates a far more serious problem.

I thought he said just.75 which is minor. I was getting an EPC light and it turned out to be the tune.

 

[GTIfan99]

I thought he said just.75 which is minor. I was getting an EPC light and it turned out to be the tune.

You seem to be confusing knock and misfire.

 

[jimlloyd40]

You seem to be confusing knock and misfire.

He didn't say anything about the number of misfires did he?