I installed white gauge overlays , and my gas gauge shot all the way up. I messed around a lil w/ it and i changed the metal things on the back of the gas & temp gauge, now both of them shoot straight up, when ya turn the igniton on, didn't touch the temp needle at all! Ya think maybe something is touching and getting crossed?

 

What happens when you start the car? If they stay you might need to take it to the dealership so they could recalibrate it.

 

when i got in today the temp gauge was at the bottom like normal, til it warmed up, then just shot straight up.
the gas gauge stays at the top

 

Sounds like a grounding issue. That's what usually will happen when you have a bad ground.

 

I have the same problem with my Temp gauge, at first I thougt it was a sensor problem but after I did my swap it does the same thing still.
I have tired checking out the connectins on the back of the gauge cluster but everything looks normal. I ened up having to get a new external temp gauge. gas gauge would suck big time.