alright so i went out and bought some iridium spark plugs because it has been 85k miles and to my knowledge the plugs had never been replaced so a few minutes ago i pull a plug and notice its a ngk tr55....is it at al possible that stock my truck came with these plugs? i thought they al were ac delco. anyways, should i change them out again or not? maybe somewhere in the 2 cam swaps i have had they decided to change the plugs for me for some reason.

 

i had some Denso plugs in mine.. i didnt know too much bout plugs on my first change, except someone told me to get TR55s.. so thats what i got..
Did you buy your truck new??
My mom put some miles on this truck i have now... 2000 @ 150k miles..

 

NGK and AC Delco combined on the newer trucks to make plugs. But i dont think they did on the 04 and back. I think they were changed.

 

yea i bought the truck new. which would be better the ac delco or the ngk tr55? the contact tip on the delcos seem more pointed like the tip of a pencil whereas the 55's are about a 16th of an inch wide circle. by contact tip i mean the part emitting the spark within the cylinder