What you were supposed to replace was the engine coolant temperature sensor (ECT), not the sensor that seed info to the temperature gauge on the dash. There are two types of ECTs - an earlier blue (I think) one and a later black one. You need the black one. If you replaced it with the correct one, make sure that the new sensor is not bad or out of spec. I just did this on my 93. The new off brand sensor was way out of spec. Replace it with a Bosch, which was in spec. You can test them by suspending the element in a pan of water and testing the resistance as the water is heated. I used a paint stir with a hole drilled in the center to suspend the ECT in the water. If the sensor checks out, check to see if the wiring is returning the correct value to the ECU. Sorry, but I can't remember which terminal to check, but the manual wil tell you. I wouldn't drive it too long until the problem is fixed. The ECT in part tells the ECU how much fuel to send to the engine. Did you get any other codes telling you you were to rich or too lean?