NGK BR7EF Plugs on Stock Tuned 2013 Denali - now issues

[gooffeyguy]

E85 is $4.60 a gallon and 91 octane at Costco or Sam's Club is $4.69. Unfortunately, E85 hasn't been inexpensive compared to gas for a very long time here in AZ.

Ouch! That's crazy, it's mostly corn grown here in the US of A

 

[Fless]

Not a great difference here, but $0.60/gal from regular is worth it to me.

 

[Geotrash]

In my area, E85 is $3.29 and premium is $4.59. It's a no-brainer.

 

[avalonandl]

I don't know why your tuner suggested THOSE NGK but they are really cold and for TURBO engines.....

 

[THarber]

Plug is too cold. For what its worth, over the years I've always stuck to AC/Delco. My Corvettes, Camaros and now Yukon don't like anything except the stock plugs.

 

[Seamus]

I believe thats the exact plug my tuner wanted in my LS7 corvette. Its a track car. But it was tuned with them in the car. I think your problem is one of three things:
1. needs to be tuned for that plug (not likely)
2. Cracked a plug when installing it (pretty common)
3. Counterfiet NGK plugs. (huge problem with NGK) have to be very sure they are authentic, and where you buy them.

If all else is Ok i would open up that gap to .40 to see if it improves
But you definitely would need a 160 stat to make that plug work, but probably would still need a tune intervention
Thats a great motor but detonation will kill it

 

[Seamus]

 

[Letcher77]

The NGK plugs I bought were from Summit so hopefully they have legit plugs. I do think those plugs are a little cold for a stock engine and after thinking about it for a while I have decided to go back to the 91 tune and not worry about running 87.

Ordered a set of NGK 7397 plugs and NGK wires from RockAuto that should deliver today. I'll gap them to .040 and install and will see if it solves the problem.

 

[Letcher77]

Swapped the plugs and wires and problem seems to be solved.