I returned from a long (1000+ mile) road trip on Sunday. I had gone 337 miles on that tank and it had between 1/8th and 1/4 tank remaining when I filled up on Tuesday. I was excited about checking my mileage and assumed, based on past experience, that it would take between 15 and 16 gallons to fill (meaning I averaged well over 20 mpg) but I nursed every last drop in there and it took 19.7 gallons. I thought, 'how is that possible? The tank is 20 gallons and my gauge indicated I had at least 20% of that left.' Then it dawned on me... I'd read about people getting as much as 25 gallons in there if they were careful (or modified the cut-off siphon) and that's exactly what happened. I've been driving for four days (over 80 miles, mostly city) yet my fuel gauge is still pegged at about 1/8th of a tank past full.

 

I have slowed the nozzle at the pumps to just a trickle and take 30 min. to get it full. By full I mean it trickles down the side of the Jeep, let it sit another 10 min. then try to put more in a no-go.

With the gauge on empty I can get about 18.7 gal. in tank and that really isn't correct. Most gauges are designed with a larger reserve when its on empty usually 3 gal. or so. The spec stated in the manual is the true capacity of the tank or should be.

 

I'm not too sure about all of that but I burn though a full tank in three days. Usually around 300 miles. 75 bucks for gas is starting to **** me off lol

 

mine always sits on full for about 100 miles after filling up.

 

Mine guzzles

 

the most i have ever gotten in my xj was 19.8 gallons. typically if i fill it immediately after the fuel light comes on i can get ~16.5 gallons in it. i might drive another 45 miles or so before i get worried.

 

This has been my past experience, too. I fill (slowly) until it squirts out the little holes in the rubber accordion thing (we have those here in California, not all states do) but it only takes between 13 and 14 gallons because I rarely let it go below 1/4 tank. This time was the same, I had a little less than 1/4 tank and it cut off at 14.5 gallons but I trickled it in just like I always do and, for some reason, it took another 5 gallons before it over-filled. I was ready to report the station to the Department of Weights and Measures for fraud. Fortunately, I held off on my strongly worded email.

I now have 115 miles on this tank and the needle has finally begun to move. It's still north of "F", though. Typically, I'll be nearing 1/2 tank with 115 miles of city driving. It's all a little weird and interesting.