During the Christmas holiday, my fuel pump died and I was out of town so I had to let a shop work on my car. When I had to fill up on my way home, I noticed that the filler was not installed correctly, which upset me. Then the tank took 18.754 gallons. I thought maybe the pump was inaccurate; it wouldn't be the first time I've encountered that. When I got home my gauge indicated that I had much more fuel than I should have and over the next few days, my mileage supported that it was in fact holding around 3 gallons more. I filled up again, 18.19 gallons once that was empty. I just added about 5 gallons so I can make it through this weekend before I drop the tank, and once again, my mileage supports the 3 extra gallons. So it really is holding about 3 more gallons than it should. I've never put more than 15 gallons in and that makes sense, it is (or was?) a 15.5 gallon tank. And it is much, much worse when cornering when the tank is almost empty.

I'm thinking they pulled some shady business because I don't see how a fuel pump replacement can also gain 3 gallons.

The car is an '88 Formula with tbi 305, 5 speed.

Is there a larger tank that fits or, since the filler is not on correctly, almost fits? Or is there some way that a stock tank can actually gain 3 gallons.
Is a part number stamped on the stock tank? If so, what should it be?
Does anyone have a picture of a stock tank?
Any of these should help me to positively determine that it is or is not stock once I have it out.

 

Well nobody has answered yet, so ill just give my 2c on the matter.

I did some looking around and found this thread, hopefully itll help a bit:

https://www.thirdgen.org/forums/body...tank-size.html

It doesnt make any sense to me that the fuel pump change would make your tank hold any more gas than before, let alone 3 gallons!! My only guess is you have a completely different tank. And it makes sense, it holds more, doesnt handle the same (heavier tank), and the filler wasnt fitting right.

I really cant think of any other reason. Maybe there is one, but im at a complete loss for an explenation for that other than a different tank.

When you find out more update us, im sure interested to see what it turns out to be.

 

No 2 ways about it.....15.5 on the stock tank so unless they replaced the tank with an aftermarket version that holds more? The pumps your using are lieing & cheating you out of $.

 

could it be a forth gen tank?