I have a 1998 dodge ram with the 5.2 liter. My check engine light intermittently come on and off and so does my fuel gauge. When i ground the singal circuit (5 v ref) to the signal return i see .02 volts. I then checked the ground circuit by by grounding the 5v ref to circuit ground with same result. So i think circuit integrity is ok but fuel level percentage does not change at all grounded or ungrounded. Just not sure if the pcm is the issue. I need to fix this so i can pass emissions

 

I'm thinking fuel pump replacement time. But I don't see how that has anything to with an emission test.

 

Part of the emission in California test is the ob2 functional check meaning the check engine light must be "off" and monitors complete. Being that my check engine is one it will be a fail. Just wondering what correlation fuel level Voltage and fuel level % is?

 

Truck only has 75k miles

 

I'm pretty sure it means the sending in the tank is bad, which is part of the fuel pump.

 

Seconded.

 

Well i dropped the tank and without installing the new pump i connected it and started playing with fuel sender. As expected i seen voltage move accordingly with the movement of the sender. Now fuel level % would initially move on the first sweep but then just stuck at 50% no matter what i did ( this also reflected on the dash). Hate just throwing parts at the problem. I suspect the pcm but not 100% sure

 

Where were you checking voltage?

 

Through a scantool.

 

Test resistance across the terminals for the gauge AT the sending unit while moving the float thru its range of motion. Resistance should change smoothly. Anything else, and it's toast.