Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Do the gauges do a full sweep when you start the car?
Sometimes they will, sometimes they won't. But if they all do except the temp gauge it's probably safe to say the gauge is bad.
A bidirectional scan tool may be able to sweep the gauges as well.