Spark plug AC DELCO or OEM Mazda

AC Delco double platinum spark plugs belong in that engine.

So I decided to I replaced my spark plugs. There was a ton of carbon build up in the first cylinder, and oil on the 2nd, 3rd and 4th spark cylinders, including the spark plugs. It’s running way smoother now but there is still some jerking but it’s not as violent as before.

I use them. Just replaced a set after they'd lasted 90,000 miles, only to rule out a very very tiny misfire count issue I've noticed lately. I might get a coil pack now, but those original plugs surely would have lasted longer (they say they should last for 100k).

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

Just did mine with ac Delco, gapped them in advance and running great!

In my personal experience (99 suburban 6.2l 383) AC Delco spark plugs are the way to go

I have ACDelcos in my 2010.

I've changed them twice over the 120k or so that I've had the car and I didn't pay attention to what was in it when I bought it, but the person who owned the car before me had a receipt from Advance.

I bought six ac delco spark plugs from Rockauto and half were made in France and half were made in the US. There are very slight differences like the diameter of the electrode and how deep the plug is on the end that goes into the cylinder. Even one of the US plugs is different from the other two.

ditch the delco plugs, they are trash. And delcos are shit plugs.

My 6.0 never ran right unless I used AC Delco. And specifically whatever the current equivalent part number is to what the manual says.