wierd thermometer activity
 

I was driving and from a stop light accelerated in first to about 3 rpm, then shifted to second. ANd as i did that, my thermometer went to 0. Then jumped back up to regular.

you most likely have a break in your guage. Its probably a potentiometer and its probably easiest to just replace it.

Make sure you look along your wiring harness to make sure there isn't any wire to wire grounds or loose ones.

good luck