04 Gas guage/sender bad but still calculating MPG?

[yakkk]

My '04 gas gauge started moving around, slowly rising from empty with low fuel light on to the correct position, a few days later it would rise to less than the correct reading, and now it's just parked on empty with the low fuel light on constantly.

After reading all the similar complaints, I'm guessing it's the fuel sensor. I've been using the "personal" trip odometer to monitor my miles so I don't run out of fuel. I cycled through the odometer settings and it's showing a mpg reading (which clears when I resent the personal trip odometer) so I'm wondering if it may be the gauge instead of the sender. Does anyone know how it determines how much fuel is consumed in order to calculate the mpg? I would think that if the sensor is not working, it would not be able to calculate mpg. Or does it use another method?

[j cAT]

the issue you have appears to be a bad sender or the wiring to it most likely at the fuel tank/in the fuel tank. low fuel indication or below E means an open circuit. usually a bad sender. pepboys sells this type failure .

the MPG computation math is not measuring how much fuel its consuming or the tank level as you drive,,,,,,, it guesses the MPG based on speed/TP/engine vacuum etc...

example when stopped you get zero MPG .

[yakkk]

Originally Posted by j cAT

the issue you have appears to be a bad sender or the wiring to it most likely at the fuel tank/in the fuel tank. low fuel indication or below E means an open circuit. usually a bad sender. pepboys sells this type failure .

the MPG computation math is not measuring how much fuel its consuming or the tank level as you drive,,,,,,, it guesses the MPG based on speed/TP/engine vacuum etc...

example when stopped you get zero MPG .

Thanks Jcat. With >150k on it I'll probably replace the pump too while it's out. I heard some recommend only the GM parts vs aftermarket, do you have any thoughts on that?

[j cAT]

Originally Posted by yakkk

Thanks Jcat. With >150k on it I'll probably replace the pump too while it's out. I heard some recommend only the GM parts vs aftermarket, do you have any thoughts on that?

ac delco or delphi pumps are used with few problems . others have issues . if the wires need be cut make sure you solder and use heat shrink .

[777stickman]

Also, try to get one that's matched to your VIN.

[yakkk]

Thanks guys!