Out of the blue, my 93 1/2 LS 400 is driving real sluggisly, for lack of a better expression. Its not running hot, oil levels are normal, however when I accelerate, its as though it is in a low gear. One mechanic states it just needs a good $560.00 tuneup, but I wanted to check around before I spend the loot. Anyone ran into this problem before? :feedback: