You need check your engine temp sensor or ECT. It's located on the head near the heater hose. It's a one-pin connecter, under the distributor. Make sure it's plugged in. If it is plugged in, it needs to be replaced. That's gonna require you draining your coolant to do it, but it's fairly easy to do, however requires patience since you'll have to remove the distributor & then reset your timing when you put it back on. Now if that doesn't do the trick, then the next best bet could be that your temp gauge in your guage cluster is busted. You can usually find new clusters on ebay or if you're lucky, your local junk yard Also, be sure to check all your fuses. That sometimes can cause an issue, too.Good luck!