from what i have read, these trucks work best with autolites or champions...foriegn made plugs work good on sports car engines and motorcycles but not as well with this type of engine setup, but then again, for some they work and some they dont, go figure

 

check this site out. i know u guys swear copper but my bosches r doin great, i even got 3 more mpg's

http://www.boschautoparts.com/Products/SparkPlugs/

 

Ok. So i bought the 3923's. What do I do with the screwy thing at the top of the plug??

 

screw it on and put a pair of pliers to it so it stays tight... gap them @ .040...

 

I got the champion RC12MCC4 from PartsAmerica. I couldn't find these plugs locally.

These were the factor brand plugs. Had to gap all. Some, the gap was closed. That wasn't going to fly!

My brother's Liberty with the 3.7 calls for NGK. That's the factory plug. He's going with the same NGK plug. Strange huh?

 

Should I apply copper never-seize to that also??

 

I put just a small dab about half the way up the plug threads, but I work on motorcycles, and since everything is aluminum, we always use it, "sparingly".

 

If you use anti-seize, use a VERY small amount, and reduce the torque of the plug when you install it. Remember that anything you put on the threads reduces the friction, and 14 lb*ft will be over-torqued. Not only can a lubricant like this cause you to over-torque the plugs, but it can also foul them if any gets on the electrodes. Use it very sparingly if you use it at all (I wouldn't).

 

i ran my firsttank of gas with the 3923's and the mileage went down. should i maybe run one more tank through and see if it gets better? does the computer need to reset with the new plugs? my power seemed to stay the same or maybe get worse, its close and cant really tell, but i know i cant feel any significant difference. i guess if i dont see a difference, im going back to the 5224's i think. any opinions?

 

I wouldn't expect a noticeable difference in mileage, from any spark plug. How much did it go down?