Skip the auto shop - Our mechanics make house calls

Q: The fuel gauge moves up and down I never know how much gas I have

asked by on

I would like to know what is wrong with it . It says full then it goes all the way down to empty . What is the part I need to replace and where is it located
My car has an automatic transmission.

The fuel sending unit is in the fuel tank mounted to the fuel pump assembly. The sending unit is shorted or open and needs to be tested using a gauge tester or by removing it and measuring the resistance of the sender by hand to see if it is working correctly. If you want to have this looked at, a technician from YourMechanic can come to your home or office to inspect the electrical wiring in your car to see if there is a simple fix, or if the car will need a sending unit replacement.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. The fuel gauge moves up and down I never know how much gas I have

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: The test says camshaft, but I put some water in the battery and now work, but not perfect

Hi there, thanks for writing in. Your camshaft position sensor is really failing, and needs to be replaced. This sensor can begin to fail for short intervals with heat and vibration, cool off, then work again for a while. Repeat...

Q: 1993 Pontiac Trans Sport. Taking longer to start.

Hello there. Many different faults can cause your 1993 Pontiac Trans Sport to crank slowly. The most common cause of this would be the battery, starter, battery cable, or fuel pump. The first item a technician will check is the...

Q: I'm having fuel pump relay problems.

Hey there, thanks for writing in about your 2001 Jeep Grand Cherokee. It sounds like you have an intermittent connection issue caused by a loose fuse holding tabs. The black you see is carbon where the voltage is jumping a...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...