Denso Spark Plug or NGK 4th gen

[OrdnanceMarine]

Did my second set of 1GR-FE plugs a few weeks ago on my dad's '08. He's had the dealership track and perform the maintenance but sure enough they hadn't changed the plugs at about 45k miles. Just like my '07 and many other members here, it had copper NGKs on one bank and copper Densos on the the other (that's how I knew they hadn't been changed). Plugs didn't look worn out but definitely had electrode wear. Went with the long life iridium NGKs and got them through Advance Auto online.

 

[d'ski]

What plugs look like @ 83K Miles

Just wanted to show and tell -- my first post here. Found a lot of great information on this site, thanks to the T4R community!

Got my 2006 4Runner in May with 79,000 miles, now up to 83,000. Confirmed plugs were never changed, Denso on pass side & NGK drivers side. Just went with the recommended Denso K20HR-U11 for replacement. I feel like the 4Runner is running more smoothly and a little more throttle response. Hopefully will see an improvement in MPG.