Yeah, I think we're screwed. There are not nearly enough of us and time is running out fast. One day we will tell our grandchildren what it was like to have once been free. They'll likely think us demented.
I am having the same problem. But mine goes up to 240 about 5 min after start-up. I checked the waterpumb with a laser temp gauge and it only reads 135. It is a new sender and a new aftermarket gauge. Sender came the gauge. The stock one starting messing up when i tried to move the needle on my gas gauge. So i replaced the gas gauge and replaced temp gauge with sending unit and ran a new wire for it.
Keep in mind that you have two senders/sensors on the YJ 4.0 liter engine. The one at the front in the thermostat housing is the sensor for the ECU and the one at the back of the block (top, drivers side, one wire attached) is for the gauge - you don't see the temperature the computer is seeing.
Both units are testable if you have a multi-meter - the resistance (ohms) changes in direct proportion to the temperature, but I don't have my manuals handy so I can't tell you what the readings should be.
on the 1993 thermistor located on top of the engine block nearest the firewall. Here are some resistance measurements you can take across it.
100 deg F = 1365 ohms
210 deg F = 115 ohms
240 deg F = 55.1 ohms
ok somthin funky when i did it i had my multi meter set on 200K the i tested one why it was a -36 anf when i switched the leads it went to 1 I tried the ground out the gauge and it pegs it so i know it is not that. I think i will take it back and get another one. Does anyone know what it should read right out of the box.