I fitted a full set of NGK LZTR4AIX-11 41,000 miles ago.

The truck runs like a champ and has never missed a beat.

My question is, I bought the Iridums for the extended life.
How long would you guys run these plugs?
I believe they are supposed to be good for 100K?
Al.

 

Hell Im still running stock plugs at 64k and not an issue.

 

i still have my stock plugs in and i got almost 100k on my truck

btw where do the new spark plugs go when I get new ones, I have looked under the hood but had no luck finding anything

 

100k is nothing for iridiums. those are 'life of truck' plugs as far as i'm concerned.

 

There are black plastic bulky caps mounted on the valve covers. i believe you take those off and the spark plugs are down inside.

 

Wouldn't hurt to pull one or two and check the gap every 30k miles.

 

Hemi's dont need spark plugs just tlc lmao... yeah them iridiums are nice thats definitely what im going to do when i change mine.... but since I blew my motor the dealer already did em score

 

Thanks for the replys everyone.
Being in the UK, I lack the knowledge & experience pool you guys have over there.
Looks like I'll be good with these.
As for regapping/checking, I believe you must be very careful with irids and other exotic metal plugs.
The coatings on the tips of these plugs is very fine and can apparently, be scrapped away using feeler gauges.
I will check them though.
Once again, cheers for the help.
Al.

 

I don't believe I've ever heard someone call a coil a 'black plastic bulky cap'.

 

how about if you run irdium plugs on a msd 6a box, still should last pretty long ??