Strange running cold problem.

So here is the deal. My Jeep doesn't like to run well when the temp. guage is below zero. More specifically, for some reason my temperature guage either shorts out or gets disconnected which causes my temp. to read below zero on the guage. When this happens the Jeep doesn't like to accelerate and if I rev the engine with it in neutral the RPM's will stay at the same speed (for about a second or two) as when I let off the gas. The problem with the acceleration is that when the temp. guage drops out the Jeep will bog down if any more than a tiny amount of gas is given (or atleast it sounds like it is bogging down). If the Jeep stalls then I have to floor the accelerator to get the Jeep to even start. Can anyone think of any thermostat related systems that would cause this to happen?

If your t'stat is stuck open, the engine will run too cool (especially now the weather's colder) and the PCM will stay in warm-up mode, causing the engine to run too rich.
Drive your Jeep for 15 minutes after a cold start, stop, and then gently squeeze the upper radiator hose while the engine's idling. This should have allowed enough time for the engine to reach normal operating temp. If the hose is hard but still feels cool, the t'stat is stuck open and should be replaced. If it's hot, the t'stat is fine and the problem is elsewhere.
What year is your Jeep?

It's a '97. I'll try that radiator hose trick. What is wierd is that the temp guage won't read anything until the Jeep us up to 210, then it shoots from 0 to 210 and the Jeep starts running like it should. I'm wondering if the temp. sender is malfunctioning and causing this to happen. Does the engine run in warm-up mode with the information from the temp. sender or from the thermostat? Is there a diffirence? Thanks.