|Originally posted by Patrick:|
That's going to vary so much from car to car, person to person... especially with a 30 year old engine of undefined condition.
Not to mention the variants of fuel tanks, and OP did not specify if he had the 4 or 5 speed manual.
Here are the min and max recorded ranges ever attained by my 1985 GT 2.8/Isuzu Fiero:
Was not planned, I was able to coast until about 20' away from a gas station's pump, then I pushed the car the remainder of the distance.
Cold (barely spring) conditions, lots of idling, traffic, town driving.
This was a fuel exhaustion test, performed in summertime on the autoroute(interstate for you USA types), around 70 MPH.
I ran out of fuel on the autoroute (as planned), then I used gasoline from my jerry can to make my way to a fuel station.
In both cases, the fuel tank was topped up, then the trip odometer was reset to zero. When fuel exhaustion occurred, I noted the value on the trip odometer.
In the instances where I exhausted the fuel tank, it took about 7.5 gallons to refill the car (and jerry can, if applicable).
OP, I recommend you perform your own fuel exhaustion tests, with a jerry can in the trunk. Do a worst-case (cold, idling, traffic) test and a best-case test (straight constant-speed highway); with these two extremes, you should have a good feel for how much fuel your car should drink.