82 300D MPG

Hey guys, just wanted to let you all know how much you've helped me in last month or so. Recently bought an 82 300D for my 16 year old daughter and have slowly, with some help from the Haynes manual and a lot from this forum, brought the car back to it's original glory. One thing, though: I recently took it out on the freeway for lunch at Galveston Bay and literally watched the fuel gauge go down. Considering I only live about 60 miles from the coast, and started with a little less than 1/2 tank, I figure I was getting about 12 miles to the gallon; AC on, 65mph the whole way. Not counting the other tips on the forum, like start of delivery, air filter, injectors, etc. is there anything majorly wrong with this thing that it gets such bad miles? Idle, acceleration, tranny is all good. No smoke. What's wrong??

I wouldn't use the tank gauge to figure out fuel economy on any vehicle, especially one that is nearly twenty years old. I've had cars with gauges that were deffinetly NOT linear; after all, it is just a potentiometer sitting in the fuel tank that "tells" the needle on the dash where to sit, and pot.s get dirty and develop shorts/opens. Use your fuel receipts and odo/tripometer to calculate MPG.

Thanks for the tip. I thought of that and found that it's still about 12-15MPG. This is drastic; like driving a big SUV.

[speedy300Dturbo]

Is the car giving off excess smoke?

Did you make sure the tires were fully inflated? You did say you changed the air filter, right?

No excess smoke, tires are properly inflated and yes, new air filter. Another thing (I hope you guys don't feel I'm abusing this forum), how do you make adjustments to the shift points on the tranny? Mine goes from 1st to second fine and spends about 2 seconds in second then jumps to 3rd and goes to fourth at about 30MPH. There are no vaccum leaks as I fixed those last week, thanks to this forum. I'm guessing the tranny works off both manifold pressure and the cable on top of the valve cover. If anybody knows how to do this as well as help me with the fuel consumption issue, I sure would appreciate it. Thanks Guys....

I've read posts here stating that these cars do shift wierd and that one should not adjust to shift otherwise. I know my 300D shifts strangely compared to most gassers, however I've driven other 300D's that shift exactly the same.
What about brakes? parking brake or callipers frozen? Any fuel leaks?

[speedy300Dturbo]

To adjust shifting points:

Turn the white knob on the throttle cable outward. It's on top of the valve cover, right next to a rubber orange sleeve that conceals part of the throttle cable.