Sending unit

2002 Buick LeSabre. How do you know if the sending unit is going out. I have noticed my fuel guage acting weird as in showing full when I know I have a quarter of a tank or less and have noticed decreased MPG and a rough idle that recovers when I gaive it some petal.

Howdy Cowboy, Sounds Like Two Problems.

Here’s my sender guess: These vehicles have sending units that go bad because of a reaction to sulfur in the gasoline. The tiny little metal “fingers” on the fuel sender’s “wiper” disintegrate, just go away. It should be possible to replace just the sender or even just the wiper. Look in your trunk, under the mat, forward of the spare tire well. If you’re lucky, you’ll have a small oval access panel with several screws, above the sender/pump assembly. Some of the GM models have it. Otherwise the tank probably has to be dropped.

The rough idle problem is another story. I wonder if an electrical problem involving both the sender and the fuel pump is a possibility. Seems like that would show up beyond idle speed as well, though. Maybe somebody has a guess for that.


Thanks I will look under the mat and let you know

Two Weeks Later And I’m Still Here!

Good. Let me know about that trunk access. I might be able to help more with the sender problem. Is this something you would try and fix yourself?

Meanwhile, maybe somebody will ask/answer about the poor mpg and rough idle. Has the “check engine” light come on at all?