Owner reviews for spark plug

I like ac delco. But I recently used denso tt fine wire plugs I two different ls engines. What a difference in power. And gas mileage.

On NGK s website it says laser iridium (the oem ones) are good for 100k miles.

So far, the OP is on to something. I’m using these plugs and that are great. Next I’m going to try the NGK ZFR6T-11G Copper Nickel. These are OEM for later 2.5 motors. I have early 2.5. I’m curious how these slightly bottler plugs will run and especially since I run premium at all times. I’ll report back. But good find OP. These work great.

The 94553 Iridiums... the tip will last longer, but the gap will widen quicker as the ground electrode does not have a platinum disc on it like the Laser Platinums, so, the Laser Platinums will last longer.

The NGK iridium I mentioned before does not have the correct reach. The website says they are the same, but they are not. I think the database is wrong. When I go back to the copper NGK that does have the correct reach, the car drives better. I had all three in my hand and the iridium is shorter from the end of the threads down (reach). NGK websites say they are the same .75 reach. They are not the same in my hands. The copper plug is. NGK 4435.

Threw new plugs in it (NGK BKR7E; I like that 3 of my cars run these now... makes life simple)

My guess is the spark plugs probably got oil on them and were fouled leading to misfires.

I’ve done an oil change as well as swapping the spark plugs and coils for brand new ones. The roughness persists!

I work on euro cars. If I'm diagnosing an issue that even has me think misfire and it has autolites, I'm done until they're in the trash can and OE is installed.

My experience with auto lite has been complete trash, and their review ratings are always great. Anybody else have problems with auto lite plugs?