Dear Tom and Ray:
So ... I'm pretty sure my ex put sugar in my gas tank. I'm positive about the sugar; can't prove that he did it. But he's crazy, and this happened the first night I had gone out on the town and was making public displays of affection with my new boyfriend. Anyway, the insurance company didn't seem to think this was a very big problem, and paid for me to get the filler tube and tank cleaned out and a new fuel pump. However, now that my '06 Xterra is back, when I get up to around 45 miles per hour and above, there is a shake and a thrumming sound in the car. And when the gas goes under 1/3 of a tank, the fuel gauge drops to "E." Above that, the "Distance to Empty" computer reading does some weird things. Any idea if pulling out the tank and fuel pump could have contributed to these problems?? I'm clueless, and I'd really like some backup for when I deal with the insurance company and shop so I don't have to shell out more dough if I don't have to. Thanks!
Tom: Note to all disgruntled and criminally insane ex-boyfriends and -husbands out there: Generally speaking, putting sugar in a gas tank will not harm an engine.
Ray: Right. My brother knows this because each of his ex-wives dumped sugar into his gas tank!
Tom: Sugar doesn't dissolve in gasoline. And the gasoline pickup tube in the tank is covered by a sock, which is a filter to keep things like sugar and dinosaur bones from getting sucked up by the fuel pump and delivered to the engine.
Ray: It's not a bad idea to get it out of there anyway, since if there's enough of it, it can block up the filter and limit the flow of gasoline. But once you clear it out of the tank, that should be the end of the story.
Tom: So in your case, I'm guessing that whoever removed the tank and changed the fuel pump screwed something up. The fuel pump and the fuel-level sending unit (which tells the gas gauge and the "distance to empty" computer how much fuel is left in the tank) are one unit on this car.
Ray: So they put in a faulty one, they put it in incorrectly or they damaged it while installing it. In any of those cases, it's up to them to make it all work right.
Tom: And while that could be the cause of the shaking, the shaking could be something else your ex did to the car (like loosen lug nuts, in which case you need to talk to the police as well as your mechanic). But make sure your mechanic test-drives the car and the shaking is gone before you accept the car back.
Ray: Start by letting your insurance company know that the car has not been fixed correctly, and that you plan to take it back to the mechanic who did the work and ask him to look at it again.
Tom: Then, do that. Let him know that it's not fixed yet. Explain the symptoms that you're getting, and ask him to take another look. And as you explain the symptoms, watch carefully, and you'll probably see an "Uh-oh, it sounds like I screwed up that job!" look in his eyes. Good luck, Marisia.
(Car Talk is a nationally syndicated column by automotive experts (and brothers) Tom and Ray Magliozzi. Write to them at the Car Talk Web site.)