Q: I have a 2004 Chevy Malibu LS with 64,000 miles. The past three times I have filled up with gas, the gas gauge needle goes to F. Then I drive about a mile and the needle falls and the low-fuel light comes on. Since I know the car has gas, I keep driving. Once I go 10 to 20 miles, the low-fuel light goes off and the needle returns to the F mark.
I don't overfill my tank. My mechanic could not find anything wrong. He thought the sensor was getting hung up. Do you have any ideas? I just got a new job, and I depend on my car.
A: The problem is in the tank sending/pump unit. There is a variable resistor on the pump hanger assembly. Most likely, the resistor has an open spot on it. Using a quality scanner, a technician can send a signal to the dashboard to check the fuel gauge operation and isolate it to the sender unit. This repair/replacement should be made when the tank is less than one-eighth full. If you can buy the sending unit without the pump, it will be a few hundred dollars.
If you buy the entire assembly, it will be around $400. Don't buy a cheap one; you will only end up replacing it very early in its life.
Larry Rubenstein is a master technician who owns a North Shore service station. Write him care of the Gloucester Daily Times, 36 Whittemore St., Gloucester, MA 01930, or send email to scan email@example.com.