how can I tune my van so that it runs on less fuel?
Replace spark plugs, wires, distributor cap and rotor, also replace air filter and oxygen sensor(s) and you should have about as much fuel efficiency as you can reasonably get.
Depending on year of the vehicle , it may have a DIS ignition system ( No distributor ) Installing a good quality spark plug helps ( Platinum plugs are best ) Having the fuel injectors cleaned/flushed , and cleaning the throttle body area will help. Make sure you also replace the PCV valve , fuel filter , and air filter . Manufacturers reccomend the Oxygen sensors be replaced at about 60k intervals , this can get expensive if the vehicle has more then one Oxygen sensor ( some vehicles have 4 , or more O2 sensors ) You might want to try going up in grade of fuel , such as from reg to mid grade , this can help in fuel economy and performance ( the computer adapts to the better grade of fuel and increases efficiency)
not being smart but if you figure it out let the rest of us know.
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