Using a good plug gapper or using even the tapered autozone one the right way you wont ruin them, but most people dont use the gap hole, they slide it up the outside till they see what the gap is. then push really hard to slide it from .040 to .050 and that takes the platnum off.

 

WRONG! They do this direct from GM, no gapping required!. 5 of my 8 gone after 20,000 miles and 2 years (bought the car new back in 97).

 

Well I had never heard that but you very well could be right. That still doesnt mean any of the aftermarkets will perform any better. There was a noticeable decline in performance when I switched to TR 55s.
Im gonna go with stock till I here of somthing better.

 

I'm surprised that you have never heard of the platinum discs falling off the OEM plugs. This is quite common. But I think you bring up a good point about GM's choice in regard to heat range etc. I'm not really sure how my +4s stack up in that regard.

 

for some reason the european cars seem to run great with the +4 but almost every american car or asian car i've seen them in was running like crap. If they are working for you thats fine, but i certainly wouldnt reccomend them....there is really no such thing as a bad spark plug or a good one. Its just having the right one for the right engine. Thats why I say the only company that did testing with your spicific car was the OEM.

 

been runnin the +4s for 2 yrs, and my car runs gr8!!! i am however going to tr55s because i just installed the nitrous(thats the only reason!)

 

well im glad to see a couple of guys running these plugs, im sure theres more out there

 

I have had the same problem with my AC Delco plugs. I had the 41-906's installed a little over a year ago and then checked them today and 1 had the pucks almost completely worn off and a couple others had pretty good wear on them. This was 13,000 miles later. I only have K&N CAI right now. I just installed some new NGK TR55's and am going to see how they do.

Also, a little interesting fact for you. The GM trucks that used the AC Delco 41-906 in 2002 now (the same GM trucks with the same engines) are using NGK TR55's out of the factory (2003 models).

I wonder why they switched???