Any year truck with a 3.0 engine should be avoided unless you plan on doing an engine swap.
The 3.4 or 2.7 engines can be swapped in easily, even though the 2.7 is a 4cyl it's HP ratings arent that far from the 6cyl engines and it makes up for the lack of HP by being a higher reving engine and returning better MPG.
3.0 engines have a head gasket issue, even after having the factory recall performed on them they still arent considered reliable, and no amount of hotrodding can make them perform much better.
3.0 engines can be found in trucks from 1988 to the late 1994, 4 Runners from 1988 to 1997.