'98 5.4 4X4...the vehicle has been sitting for 8 yrs and fired right up after minor maintenance...but it has an Eng Temp gauge that will peg full hot after 15-20 min running...the gauge will return to normal operating temp sometimes or if engine is turned off...but will return to full hot after a short run...Check Engine light comes on if I run the truck with the pegged gauge...the check engine light so far has gone off each time after a period of time...since the gauge sometimes returns back to normal operating range while the truck is running... I assume the engine is not over-heating and there is no indication that it is....do I have a faulty gauge???? sensor???? and is running with the check engine light damaging anything???? Can't get smog check with Engine Light on...fixable????

 

So, how long is a "short run" and during the short run, do you drive it at all?
As far as the engine light, i would get it checked out but I have been running a Ram with an engine light on for about a year now (not my primary truck) and it hasn't hurt anything so far.
About the gauge, turn the key to the On position and do any of the gauges read anything, if so, what does the temp gauge say when it's just in the On position?