i think so too, but when i put in tr-55s in my truck gapped at .55 it ran like crap... Talked to a knowledgable tuner, he said that i would have to increase the dwell time a little bit to compensate for the larger gap... I just put the stockers back in rather than screwing with a table i know nothing about...

 

It's due to the iridium plugs, I don't know the exact science behind it, but iridium plugs generally have a smaller gap, and usually come pre-gapped since it's so easy to break the tips off of them. You can't gap iridium plugs the old way where you pry between the ground and the electrode, you have to grab the ground only, or the tiny iridium tip may break off.

 

thats how i gap my non-irridiums...a bench vice. i dont like touching the electrode thingy. it just doesnt seem right haha.

 

Yea, it's best not to pry against the electrode on any kind of spark plug. I usually use needle nose pliers

 

I checked the gap on my old plugs that i pulled out, they we're gapped to .055, the same as the ngks i put in. On a brighter note, when pulling off my wires to check all their connections, 2 pulled apart right at the plug, one on each side. I'm hoping they were already torn, causing the problem. Running on 6cyl could be the reason why it felt sluggish.