Skip the auto shop - Our mechanics make house calls

Q: Gas gauge needle fluctuates up and down

asked by on

We just bought this car yesterday, it has 110,000 miles but was checked out by our mechanic and he gave us an excellent report. We had to put fuel in so we filled it up and drove 6 miles home. In that short period the needle fluctuated from full-over full to 3/4 a tank! I know these cars are supposed to get good gas mileage so what would cause the needle to do this? We are still within our 72 hours return so I am looking for a quick answer. Thank you!!!!
My car has a manual transmission.

This may possibly be a faulty fuel tank sending unit. This is a float type designed sending unit that sits inside your fuel tank that monitors the fuel level inside the tank. When this is faulty or failing it can cause intermittent changes in the fuel gauge to register as you describe.

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!

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: Vehicle hard starting & fuel economy issue.

Check for proper fuel pressure - both while the vehicle is running, and after running. I suspect you will find that fuel pressure is not being maintained in the pressurized portion of the system due to a fuel pressure regulator...

Q: I changed out my starter but now I think it's not disengaging took it off went to test it they say it does disengage what else c

It sounds like you have three issues: a possibly faulty battery, a no start condition, and noise on starter engagement. The condition of the battery can be verified through a load test. If the battery checks out OK, once you...

Q: How does the automatic moon roof work?

moon roofs are great – they let in light and air, and they make your car feel larger than it is. Your car’s moon roof offers simple operation, but there are a few things you need to know before you...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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...