Temp Gauge Innacuracy?

Ok for the past couple weeks since I put my 180deg thermostat in my temp gauge will peg (though the check gauge light never comes on)... I noticed as I turned the headlights on and the a/c or climate control in general or my fog lights and stereo system the temp gauge would go up... I hooked up my AutoXray and the coolant temp got to a max of 215 when I was racing last night. and then stayed between 190-215 the rest of the night unless I was sitting... I tried unplugging the a/c compressor so I could keep the fan on all the time and it dropped quite a bit on the gauge... any ideas? bad ground somewhere?

Think I might've found the issue... TSB 95-18-5 new sender and gauge

n/m (haven't done the TSB Yet) the oil pressure gauge is pegged too... still no check gauge lights though..

Well, I think I got it... what I discovered was that it's a bad block ground (ground to engine block) I hooked up a jumper cable to the negative battery terminal and then to the engine and the gauge went back to normal... so looks like i need to try and track that ground cable down and replace it. anyone know?