Wrong size plugs in Tundra 5.7L???

[BAJA_05]

Pulled 8 of these out of Tundra in signature. LFR6A11 NGK Iridium 4s. Plugs I matched up with Rock Auto has on the box LFR6T11. So the Iridium 4s in my manual say they go in the 4.7L... I have the ones from Rock Auto in the truck. Other plugs thrown no codes though. Much beefier now with throttle, shifts better for some reason through the tranny, mpgs is better already. Picture is the old plug I removed. Mind boggling... SMH

Ps. 3 of the plugs felt like they were only finger tight when I pulled them out. Put almost zero pressure on the ratchet.

 

[FatOrangeCat]

Possibly the previous owner wanted a plug with a different heat range. Or just a mix-up in PNs at the last plug change. Glad you are seeing performance improvements!

 

[FowVay]

The owner's manual is funny about this. It lists NGK and Denso for the 4.0 and 4.7 liter engines but only Denso for the 5.7 liter engine. The Denso for the 5.7 liter engine has one extra letter in the identification so there's something different. The manual states the 5.7 uses a long reach plug and the 4.0 and 4.7 use regular reach plugs. For a RockAuto purchase you'd search for Denso 3421 if you want the SK20HR11 item.