I'm late to the game, but agree with above sentiments. I currently have Ruthenium spark plugs in my supercharged engine as it has a shortened ground strap to open up the flame kernel with less obstruction. I'm chasing fraction of a HP at this point but my engine eats iridium electrode plugs for breakfast so I'm trying other things. I was using Iridium IK22's and those would last 15K miles before they'd open up so much the engine would misfire. I could adjust the gap but by 25K miles they were in the trash. Tried IK24's, a step colder but those carbon fouled around town so those went in the trash early as well.

On my last Toyota I used to run copper 'V-Power' plugs that had a split center electrode so it wore out slower. Doesn't work on our 5VZ-FE but those plugs lasted for darn near forever. Same goes with the copper plugs for the 5VZ-FE, NGK or DENSO doesn't matter as from the factory they came with both brands! Like you said though, for $3.65 you can change all 6 for less than $25. I spent $75 on the Ruthenium plugs...

Next time you need a set, get them from Rock Auto: NGK 96457 Spark Plug | RockAuto

The problem with most plugs in a wasted spark system is that the spark goes "both ways" - and sucks material off the ground strap much faster than a 'unidirectional' spark (usually not a special material, just the main electrode is). The Ruthenium's should work better for you.

The V-Power plugs are great in my 3s-gte. I still change them every 15k-30k though...

-Charlie

In your instance converting to coil on plug or a MSD DIS4 may help.

If I had a spare ICM I’d probably pull the trigger on paralleling two coils per OEM coil connector and use a ford or mopar coil on plug coil. My 4.7 (in my Grand Cherokee) ignition coils would fire a 3/16” gap. I pulled the plugs with 68k miles on them and the electrode was worn down all the way to the ceramic. With wasted spark the coil fires over twice the gap of coil on plug.


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