Fuel gauges are factory set and are not adjustable. If inaccurate fuel levels are experienced the most likely cause is a bad sending unit.
either the fuel gauge needs replacing or the fuel gauge sending unit in the fuel tank is stuck
check your converter on exhaust, also check the air flow meter it is in between air cleaner and engine
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Inside the fuel tank with the sending unit for your fuel gauge
To adjust the fuel level, you should begin by putting fuel into the 1967 F-250 diesel engine tank. The fuel gauge will rise according to the amount of fuel purchased.
The electric fuel pump is inside the fuel tank along with the sending unit for the fuel gauge
a mechanic told me that the fuel pump has a loose ground wire low fuel to current fuel level over and over again. my 2000 did that
You will have to remove the gas tank and install a fuel control module. Before you do you need to have someone check for power and especially the ground for the fuel gauge.
If the fuel gauge on your 2000 Montana always reads full, it could be due to a faulty fuel level sending unit, which is responsible for sending the correct fuel level information to the gauge. Additionally, there may be an issue with the wiring or the gauge itself, causing it to malfunction. Another possibility is a short circuit, which can send a constant signal to the gauge. It's advisable to have the vehicle inspected by a mechanic to diagnose and fix the issue.
Most of the time it's the fuel level sender in the fuel tank if your gauge moves around a bit but doesn't read correctly. If the Gauge is stuck on full all the time, the gauge itself is broken.
All fuel sending units are located in the fuel tank.
I have found though my experiences that 99% of the time the fuel gauge sending unit in the tank has failed.