Subaru Repair: 93 legacy AWD wagon fuel gauge, fuel gauge, fuel tank

Question
I have a 93 legacy AWD wagon. The fuel gauge is working, but not accurately. When you fill the tank it might go to just below the 3/4 full line. The first 100 to 150 miles it goes from there to 1/4 full and all points in between. At around the 200 mile mark it calms down a bit and shows 1/4 full and goes down from there. When it is completely empty the needle is buried to the bottom. I am thinking that it is a float issue in one of the sending units, but I am not sure and do not want to pull the sending units unless it is necessary. How do I test to ensure that it is a sending unit? And which sending unit (there are 2) should I test first?

Answer
Sounds like you are on the right path, and that you have a float or sender issue. Unfortunately, Subaru does not have a good test for which sender to replace. They actually used to have a bulletin out that said to replace both. The only good thing is, it is not that hard. The fuel pump/sender are under the back seat, so no fuel tank to drain and drop.

I tried to use my online sources to double check things, but neither are of much help. I will check the actual service manual on Monday and let you know that night if I find anything that might be of more help.

Good luck