Sorry to tell you. Your mechanic doesn't know his 3.8L'* overly well. You described the symptoms on an internet forum and got the answer. He looked it over in person and misdiagnosed it. The plugs were wet and goopy because they had coolant on them. Probably overdue for a change..but still. Crank sensor was probably not bad, the coolant doesn't burn well and causes what you mentioned. Most mechanics have seen the bad UIM many times on 3.8L'* because it'* the most common failure on them.
Hopefully you caught the UIM in time and all is well when you change out the manifold. PS, please change your LIM gaskets at the same time. They will look horrible and need to be changed.
Originally Posted by Unreachable
well gentlemen........good news car now runs........bad news still misfiring not as bad, and it'* still blowing white smoke. AND and this deserves a big AND there was no coolant in the holding tank. SO 3 problems fixed... new crank sensor=done new spark plugs=done car runs=check...... more then likely new intake gaskets to come. F*CKING A..... what a hassle..... will know more info Monday or Tuesday when he has more time to look into it.