Honestly, with the stuff you have already done, you may have gained about all you will get out of your van. You probably need to get it going and drive it a few months and get real gas mileage numbers.

You may gain better gas mileage by changing how you drive the van. I can get 2-3 mpg better mileage then my wife driving the same vehicle, she has a bigger lead foot then I do, and I don't drive for the best gas mileage. drive Want better gas mileage? Don't drive like I do.

The best investment you may make for getting better gas mileage is to buy and install a vacuum gauge, and never let the needle drop below 15 while your driving. Your van will probably get the best gas mileage at 55 mph, or maybe 60, or maybe 50! Any speed above that reduces the gas mileage most of the time, you have to find the speed the van likes to run. Driving for the best gas mileage is a learned art, and you have to be 100% dedicated to it, one slip up can kill the mileage for the whole tank full. Gene