Spark plug NGK or AC DELCO

Im tuned and on an E85 mix but using 1 step colder NGK's (#ILZKBR7B8DG) gapped to about 0.022...needed these before I even went MHD though. Once I did most of my maintenance, the car required this for proper spark. Night and day of a difference.

I still put a small dab even though the NGK plugs recommend against it. I change my plugs every 15-20k because I have a tuned Focus ST. I already went through 3 sets of NGKs with no problems doing the small dab

I've had multiple Chevy engines that gave random misfire codes with autolite plugs- then ran fine on ngk.

I replaced them with AC Delco 14 Platinums, and it seems to be running better.

If you want relatively inexpensive and decent look up whatever NGK plug is correct for your car.

I find the car runs way better on the Rutheniums, and I find that the plug gap doesn’t open itself up over time like it was with 6510s.

I went NGK and noticed a small bump in throttle response, changed mine at 100k Km (60k miles) and they were honestly good to throw back in too, so not like the plugs were burnt or fried!

I’ve been running NGK Ruthenium plugs on my stage 1 GTI for 20k miles. No issues.

Yesterday my new Ariens made its maiden voyage up here in Maine and began misfiring under load. Called the dealer where I bought it and they said it may be the spark plug. Ariens apparently puts cheap Chinese plugs (Torch brand) in their machines. Long story short, new NGK and all is well. Powers through them berms like a pro.

Now that I've done the job, I can't tell if it's just in my head but the car seems to have less power now. It was already a sluggish engine to begin with it but it feels like I need to floor it even more. Also, the gas mileage has dropped from 25 MPG to 22.5 MPG.