OK I had erratic readings on my fuel gauge I replaced both main and sub sensors.. SO the fuel gauge starts to go up to about 3/4 of a tank.. So I got a little curious because I almost did 60 miles at about a avg speed of 40 MPH (snow) and I'm like this in no way can be right.. so I went to put a full tank of fuel in and the car took 10 gal of fuel with the gauge showing 3/4..
So being as I replaced both fuel senders do I look at the gauge it's self now for maybe a screw that's not making good contact?
My 95 BK was having the same issues with the readings,i would fill the tank all the way up and it would only read 3/4 full but the car was sitting for long periods of time and not being used when this issue started. Now i have been using the car daily and for some reason the guage is now working again accurately.
You should've checked the fuel sender before replacing it. You could have a bad gauge, which since you replaced the sender then I would say it is the gauge. Btw our fuel tanks holds a total of 15.9 gallons and when the low fuel light comes on there's a little over 3 gallons left.
Now that I think about it I've never replaced a fuel sender or a pump on a Subaru. Well I have but they've been upgraded pumps. They along with the other Japanese cars have always used great quality pumps for sure.