Sorry 4Runner and GX are the same, sequoia and tundra are not the same v8.
Back on topic, he's way over due on maintenance as previously stated.
Sequoia and Tundra 4.7 V8's some were built in Alabama, some were Japan built I believe in the early years, say '99-'03. The vehicles were assembled at the old Indiana plant until 2010 I believe when production was moved to Texas.
There was a difference in the 4.7 internals after about 2003. The 4.7 supercharger is not recommended for later model years because the piston rods were weaker, something about the forging process made them unable to handle the boost from the TRD supercharger.
I don't know if the 4.7 internals differed from year to year with Japan built vs. US built, but something changed somewhere around 2003 so some Tundra 4.7's were blowing rods out of the block with the the TRD supercharger. Later model 4.7 Tundra owners buy aftermarket rods so they can put the supercharger in.
All 4.7's have a timing belt, though.
It's interesting the differences in HP and torque ratings between the various 4.7's produced. For instance, this '07 4.7 I have is rated lower in HP and torque compared to my '05 Tundra 4.7 or an '06 Tundra 4.7 after the SAE measurement standards were revised. This Runner by my seatofthepants feel does not have as much getup and go compared to the '05 Tundra (which weighs 4920 lbs unloaded, I weighed it).
Could be I just need replace sparkplugs, clean the MAF, and fulltime 4WD may drag on it some. Nevertheless, the published HP/torque ratings are lower for the Runner 4.7 vs the Tundra 4.7, or the Land Cruiser 4.7.