Tach @ 0 works occasionally/ engine shudders when warm

I have a 1990 SC 3.8
Recently I had a problem with a hole in the high pressure line leading to my rack and pinion. After fixing the problem, I developed another problem....

I developed a whistle and could not figure it out. After a week of this getting louder and louder the engine started to shake violently after warming up. About 10-15 miles. Being that I drive 100 miles a day to work, this is getting a little anoying. I have found if I turn it off and on while in gear and moving, the problem sometimes goes away. Most of the time my tach is at zero but works occasionally. I think that when I reassembled the piping to the supercharger I didn't get things quite square. I have since taken it back apart to replace my negative battery cable. The whistle is gone but the engine shudder is not. I am wondering if during the week I drove it I caused the timing to get so far out of whack that this is causing my problems. I don't know what is the next course of action.

Please Help !!!!