Bouncing Tack needle???

[Big House]

This is whatI saw coming home tonight after the sall install. While cruzing, and I get off the gas...the tach neddle would "bounce between 750 and 1500 rpm. I give it some gas and it is back to normal. Never seen this before. It didn't last long but it did it for about 10 or so minutes. Anyone ever see this. On one note it stopped and the tachfunction resumed normal operation. In all of this the motor never sounded nor did ythe car ever feel like it was surging. Any guesses?

[Bradley G]

How many licks did it take? :lol:

[Breadfan]

Hows your battery doing? Sometimes when batteries are dying and their voltage output is either low or erratic it can cause the electronic gauges to act up...

[whoskal]

I used to have an Explorer that did that with the MPH.. sometimes I didnt know how fast I was going cause the needle was bouncing around so much....turned out to be a bad relay.