Toyota recalls approximately 62,000 non-hybrid Tundras for a camshaft defect. Here are the model years and what owners should do. (read full article...)
Just kill that engine and stick a proper V8 in the Tundra for crying out loud.
On a side note, have you ever checked to see if the Tundra you had a few years ago has had an engine replacement? I would think you could put the VIN into carfax and check it.