I have the same problem with my 94 Nissan XE 4x4, V6. The speedometer went out just before 100,000 miles. It doesn't move till I get to around 40, then it just bounces around. Awhile later the tachometer quit being reliable. I also get the check engine light and ABS light coming on and off for no reason.
The only thing I can figure is that some control module, maybe under the passenger seat, is slowly going out. This seems to be a common problem for this truck and I wish someone could give me an answer as to what's going on.
Thursday, November 22nd, 2007 AT 9:39 PM