It is 20degrees here in Chicagoland, and when I started my truck this morning and for the first 10 minutes after start up the tachometer and speedometer needles were bouncing all over the place without the engines rpm's or my speed changing. After the 10 minutes and I was on the expressway things went back to normal. Any ideas what went wrong and what I should be looking for? 1993 6.5TD Silverado
Thank you

I've had weird gauge action when I had an electrical problem. This problem has been: bad or weak batteries, bad grounds, bad alternator. Might just be the cold and some tired batteries in your case.

Try doing a search - there was a recent thread about this.

Here is the recent thread on the subject. Not sure that there is a real answer to the problem, other than it seems to be happening to several people.

http://www.dieselplace.com/forum/showthread.php?t=118447

Dave