2004 mazda 6 with 3.0l V6..WHen the gas guage falls below a quarter tank the car shutters really bad getting on and off the interstate. Almost as if no gas is getting pushed to the engine. Dealer ship said without a code they cant fix it unless it breaks completely. Fuel Pump?

Fuel pumps outside the gas tank have nothing to do with fuel gauge readings. There is a fuel level sender unit inside the tank with a float which supplys variable ground circuit to the gauge. If you can find the wire to this unit, you can ground it to see if the gauge now goes to full. If so, sender unit in tank is bad, or has bad wiring/ground.

Go and get your wheel alignment checked out

For a 1989 Honda Civic, to remove the fuel pump after you've removed the tank, disconnect the fuel lines and connector, then remove the fuel pump mounting nuts. If there's a ring, unscrew it to remove the fuel pump. ------------------------------------------------------------------------------
Digimaster 18

The gas tank sounds like a bad ground usually located under the car at the gas tank. I do not know but maybe they both tach and fuel gague get their ground from the same place.

SOUND LIKE FUEL PUMP CHECK VALVE IS BAD.IT ALLOW ALL FUEL DRAIN BACK IN TANK.

well either the fuel sender got caught on the tank baffle or your other sender was going bad

THIS PROBLEM IS ONLY CAUSED BY ONE THING, AND THAT IS A DEFECTIVE GAS GAUGE SENDING UNIT IN THE GAS TANK

Sounds like a bad sending unit which is mounted in the gas tank and has to be dropped to get at it.

The float that helps detect fuel level is most likely broken. You or a mechanic will have to remove the fuel pump from the gas tank and check and possibly replace the float. Merry Christmas.

your car has a electronic pump. sometimes in cold weather it will lag causing your fuel to be slow getting to your injectors. the humming is probably your electronic fuel pump. it could also be a exhaust leak. nothing big but just check your exhaust and all. now for the reason your fuel guage might be strange is because your float is located inside your tank, cold fuel will cause the float to stick sometimes and will throw off your guage