Just swapped out the champion RC12LC4 plugs i bought the truck with, for autolite 3923s.

Also did air- the left sides were at 26 pounds, lefts at 27. sidewalls say max load is at 44 psi, so I put them at 35. Did I put too much in them? (ext cab) 265/70-16 firestone ATs

I was getting 12.5-13.5 mpg before. Gonna see how much this helps.

The gaps coming out were between 50 and 55. going in were between 40 and 45.

 

35psi is what most ppl run on here.

 

I run 36 on my bfg's my goodyear spare says 50!! thats not the max either

 

psi sounds good to me I usually put a little less in the back since there is like no weight compared to the front but that sounds about right...and as far as a magnum motor sounds like good plugs...I just did ngk v powers and couldn't tell a difference between them and my autolites but they were mighty dirty when I pulled them so glad I did it.

 

35 psi is about right. I ran my tires (Firestone Destination LE 23575R15's) at 42-44 psi for a while trying to get better MPG, it helped a little but wore the center of the tread down a lot faster than it should have.

Jimmy

 

thats what i have, destination AT

 

Yep these Destination LE's have been a really good tire for the money. I paid $422.00 for the set, mounted, balanced out the door with lifetime rotation and balance and road hazard policy at Tires Plus 2 years ago.

They have 40,000 miles now and still have good tread left. They hold air very well, have a good agressive tread pattern for a highway tire and they get great traction in the rain and on dry roads. I don't go off road. They have become a little noisy in their old age but are still a great tire. I'll probably get at least 50,000 to 55,000 miles out them. I'm keeping my eyes open for deals and sales on another set between now and next summer.

Jimmy

 

i just put in the same plugs last week. engine seems a little smoother but after 1 tank no mileage difference from the stock plugs.

my tires are also at 35 psi in the back and 36 in the front i think it helps with stoping and steering.

 

$480 here from the firestone store. I've only put a few thou on them. I bought them based on the tire rack reviews of 50K+ miles on a set. Figure if I get 40 I'll be happy- last few sets (goodyear, goodyear, toyo) i've barely gotten any life out of at all.