87 Accord LXi (fuel injection), 255,000 miles. After a mechanic replaced the fuel pump (see note below) and filters, I've been having a consistent problem.

With the gas gauge showing 1/4 tank, the car seems to run out of gas. Refilling the tank--or even just adding a couple of gallons--fixes the problem. I think the gauge is correct. The tank has about 15 gal capacity and when I refill it, it only takes 9 gallons. Also, tracking the gas mileage indicates there should be 1/4 tank.

I've gone through this process about four times. Every time I reach the 1/4 tank mark again, the engine dies just like it's out of gas. I do get some warning: Starting about 40 miles before the engine fully quits, it starts to hesitate like it's lean. I clutch or back off the throttle and it won't stall. As I get closer to the "empty" point, this happens more frequently.

The mechanic says he doesn't have a clue...and I believe him.

If it were a clogged filter or the fuel pump, I would expect the problem would occur no matter how much fuel was in the tank. Is it possible he mounted the fuel pump and its intake incorrectly in the fuel tank?

Note: The fuel pump was replaced because the car wouldn't start and the mechanic diagnosed the cause as a fuel pump issue. We first became aware of this "1/4 tank empty" issue when he took the car for a test drive after changing the fuel pump and it ran out of gas. He complained the fuel gauge was wrong though it had never been wrong before. Perhaps the "1/4 tank empty" issue pre-dated changing the fuel pump (and perhaps the pump didn't need to be replaced).

Perhaps when he was fixing the pump, he messed up the in-tank sensor somehow? Are you sure it only takes 9 gallons at the most?

Thanks for looking at my problem!

The in-tank sensor leads to the fuel guage, right? I'm 99% sure the fuel guage is okay; I'm sure it only takes 9 gallons max to refill the tank. I've run it down to the "1/4 tank empty" stage at least four times to confirm. Then I either refill the tank and it's always about 9 gallons to refill it, or I add just a couple of gallons to see what happens. When I add just a couple of gallons, the car runs fine for about a couple of gallons worth of mileage and then sputter, sputter, sputter. One more piece of evidence: I usually get 360 miles to a tank of gas and I'm only getting 260 before it quits.

Could it be a clogged air vent? I've looked at line drawings of the fuel tank but I can't figure out where the vent is.

This is really odd. I have a few thoughts, but nothing really definitive.

I would pretty much rule out a clogged vent or filter or anything of that nature, because that would cause issues all the time I would think

I really think you need to drop the tank again, because something doesn't add up. Either hte pump was installed incorrectly, or not hte right pump, and doesn't reach low enough in the tank. Or the sensor is screwed up. Or for some reason, you got a smaller gas tank swapped on unbeknownst to you.

The point is, this mechanic obviously was the last person to screw with the fuel pump/tank, and obviously that is the source of the problem. I'd take it back to him, explain the issue and ask him to drop the tank again, or recheck his installation, because something was done incorrectly.

My guess is the fuel pickup got bent or misdirected during the replacement, and now sits too high where it can't reach the bottom few gallons of gas....

http://www.autozone.com/images/cds/jpg/small/0900823d800d09d2.jpg

It looks like this...if the bracket is bent, the pump doesn't have the reach it should have...