Do 79's have a inner liner in the fuel tank? The 79 I bought last summer I have finally gotten a chance to drive. Twice I have let the fuel get down to the point that the low fuel indicator was on full time. When I fill up the tank, both times I could only get in between 16 and 16.5 gallons. The owners manual says it should have a 23.7 gallon tank. I have looked at the tank and don't see and dents in it that would decrease the capacity. Is there an inner liner that has collapsed or do I have a gauge problem.