I have a 1989 Honda Prelude 4ws si and when ever i turn my blinker on the temperature gauge goes from normal to bouncing on the H. and if i drive for like 5 miles the temperature gauge will go from normal to hot but if i push on the dash it goes back to normal. However my car never runs hot.

I would say that this is a wiring issue. You would have to inspect the wiring underneath the dashboard and the one that leads to the gas tank. One is the power for fuel pump and the other is for the floater for the gauge. Check for loose wires especially for exposed conductors or worn out insulation. The wire might be touching the wire for the blinker causing the issue you are seeing.