My truck is a 1998 and since I’ve had it for about two years now it’s always had wrong readings on the cluster but just for my MPH and my engine temp reading Even when key on ignition off, my miles per hour doesn’t sit on the stopper and my temp never goes above 1/4 of the way. I have measured and made sure that my truck is at operating temperature and I know it is +10 mph because of live data monitoring via obd.

This image is me sitting still in a parking lot after 15 minute drive so we are at normal operating temperature

 

You should always include engine size

2.5l 4cyl?
Temp gauge is about right for the 2.3l/2.5l Lima SOHC engines
Ford put the temp sender at the driver side rear of the engine instead of at the top front where it should see 185-195degF
So if you checked the upper rad hose after warm up and it was above 180degF then all is well, and heater blows HOT
If not then thermostat is stuck partially open, which is the correct failure mode, if they fail

Temp sender is just below the oil pressure sender, driver side rear, seen here: https://cimg4.ibsrv.net/gimg/www.ran...96a27c731c.gif

These are SENDERS not sensors, so are 12volt devices, and often just have 1 wire, senders are only used by gauges
Sensors are 5volts and always have at least 2 wires
There is an ECT(engine coolant temp) sensor at the front upper engine, only used by computer, 2 wire, was on a heater hose in some years


Cluster has been out, or swapped, and the speedometer need was set wrong
Calibrating the electric speedometer needle is a pain, need to pull out the cluster and then use a AA battery hooked to speedometer motor

Easy and more actuate way is to pull the cluster's plastic shield off, use a fork to lift off speedometer needle
Go for a drive and maintain say 40MPH on GPS, push the needle back on so it shows 40MPH, then come to a stop and see of its at 0MPH then drive again up to 60-70MPH and see if it matches GPS
May have to adjust it a few times, cruise control helps, lol

Or just swap the cluster out, 1996 thru 2003 Rangers or Mazda B-series are interchangeable, plug and play, with or without tachometer


Always change the 6 backlight bulbs when a cluster is out or swapped, they are cheap and a pain to get at
You can use LEDs just have to MAKE SURE to put them in the right way, LEDs have a + and - side, regular bulbs do not
Doesn't hurt the LED to put it in backwards, just doesn't light up