I was driving around last night and sat at a light and watched my dummy temp gauge going to "H". The light turned and it went down right away, but my Autometer temp stayed at 150. It's been doing it sometimes when the car times down too. The fans are running and my autometer never goes past 180. I know there's something wrong w/ the cooling system in general since the res. is always empty after being topped off and going then going on a 5 minute drive. I don't suspect blown HG. I'd imagine either that my dummy gauge is going to crap, the sender's for both gauges are not "T"ed correctly, or something is going on with my thermostat(which is less than 2000 miles old).

i think its 190. i'm pretty sure that the top sensor on the T-stat housing is the coolant temp sensor that sends the signal to the ecu. the bottom one is the one that controls the stock temp gauge. might wanna check them both. also if you have the stock and autometer senders "T"'d it could be causing the problem because they are supposed to be directly in the flow of the coolant.

the valve opening temp of the thermostat is 195F
the full opening temp of the thermostat is 216F

also, maybe you are low on coolant? my resevoir never runs out, it is always full.

Yeah, sounds like very low on coolant. The autometer probe and dummy temp sensor are in different locations, so it makes sense that they'd read different temps if one was reading steam and the other very hot water.