my truck likes platinum plugs.

purpl, the big deal about platinum plugs is that they last longer. so instead of having to change them at 12k, you don't have to change them until 50-100k.

 

Thanks for all the input!

 

The copper Autolite 3923's last that long in my truck

 

I change the regular Copper Cores every 15,000-20,000 miles. Otherwise the idle gets somewhat rough and winter starting is harder. The only plugs I would trust for a 100K change interval would be some Iridium plugs. But I would never go that far on this truck, as the amount of rust that builds up in the spark plug area on the head because of those heat sheilds makes the plugs a pain to get out.

 

how often do you pull them to check the gap/condition? i only say 12k because laramie (i'm pretty sure it was him) gets about that much before they need replacing.
anti-seize and not tightening them down too much makes them easy to take out.

 

I never check spark plugs unless I start losing performance.

 

I check mine all the time. You can learn a lot about what's going on in your engine from what you see on your plugs.

 

I use plenty of anti-seize and torque them to the FSM's specs (I forget what it is!). The heat cycles of every engine varies, the type of climate you drive in, the amount of miles on your engine, and even imperfections in the spark plug due to mass production are all factors that go into that. After 13,000 miles, the 2-4-6-8 Autolite Platinum 3923 spark plugs were all loose. I blame that partly because the design of the 3923 plug does not have a crush washer. Then I took them all out, re-gapped them, put them back in, and torqued them down. Then the next day I had a horrible misfire from cylinders 2-4-6-8. Replaced them with the factory Champion RC12LC4 plugs. Runs better now with the Champions than it ever did on the Autolites, even if it pings a little more. I probably should go ahead and swap them out again for a set of colder Chanmpions (RC10YC).

 

The ones I have now got 40,000 on them.Still starts quick,idles and runs smooth with no miss,and decent mpg(15). They are cheeap enough,If I pull them out,they go in the trash.