Tachometer is acting more like an engine hour meter

Hi,

I just purchased a 96 J30T. Great car for the money,....the
tachometer is acting very strange. Every time I start the car the
tach is at "0" as the car continues to run, the tach very slowly and steadily rises until it is at its full clockwise position past redline. It
stays there until I shut the car off and then it starts at "0"
again. It seems to take about 20-30 minutes for the tach
needle/indicator to make the circle around the face of the tach to
its final resting position past the redline. The Tach NEVER gives
any indication that it is moving in relation to engine RPM.

My experience is that most anomolies like this are design related
and that others with the same car experience the same problem.

Has anyone experienced this? If so, Can it be fixed??

Please respond to my direct email address or copy me at:

bc1@joimail.com

Thanks in advance,
Brian Collins
Dallas, TX