3.4 is a much better engine than the 3.slow, they share very few if any parts, non interference engine if the T-belt breaks, replacing the belt isn't all that tough, lots of bottom end torque compared to most older Toyota engines.
if you can't verify maint. history, do the normal, belts, hoses, filters, clean the MAF, tighten valve cover bolts, change the spark plugs ( they are supposed to have dual electrode tips NOT PLATINUM )
if it is Auto, check the trans fluid, and disconnect the trans cooler from rad and install remote cooler ( rad. cooler will eventually crack allowing coolant into trans, which won't last long after.... search toyota boards for "strawberry milkshake" )
CV joint on rear shaft has probably never been greased, good luck
check rear brakes for gear lube intrusion, means the axle seal and bearing are shot, not too bad if you have half a clue and some know how ( I made a tool to remove the axle bearings from an old axle housing and some scrap steel )
