Improving gas mileage?

Has any one heard of any means of improving gas mileage on Montanas, Ventures, etc? My Montana gets only 21mpgUS/26mpgC based on about 10000K of careful records. This is considerably below what either the US or Canadian manufacturer claims are. I was wondering if there are any means of tweaking; chips, air flow, whatever?

There are several things that you can do. Make sure air filter is clean, tires are inflated to max pressure, and use only 4.5 quarts of 5W-30 preferably full synthetic or 0W-30 full syn. If engine is even 0.5 quart overfilled, it will kill your mileage ( personal Experience). Also, Shell brand gas claims to give better milage. There are a few other non traditional things that can be done. Slow down to 55 instead of 65 = 3 mpg increase, do not stop for stop signs or stop lights (not recommended).

I would also suggest using a fuel injector cleaner product. You can also change your plugs to something that provides more complete combustion, such as Bosch platinum 4. These are what I run in my 2000 Venture and I get about 28 mpg as long as I drive reasonably.

I would also suggest using a fuel injector cleaner product. You can also change your plugs to something that provides more complete combustion, such as Bosch platinum 4. These are what I run in my 2000 Venture and I get about 28 mpg as long as I drive reasonably.
In my personal experiences, I would NOT run anything but AC Delcos in the vehicle. I made that mistake once and those plugs caused too many problems. Once the Delcos were reinstalled the problems disappeared. I have sold hundreds of plugs over the years and the customers who bought Bosch and other brands were more likely to come back and complain and then purchase the AC Delco plugs to go back into their vehicle. The other aftermarket plugs can cause rough idling, poor starting , poor cold weather performance, poor mileage, and shortened life. I have owned about 19 vehicles in the last 21 years, most of then GM and they ALL had AC Delcos in them and never had a problem. When you're talking about a vehicle like the Venture you only want to change the plugs once as they are extremely difficult to remove the 3 in the back of the engine. You don't want to have problems with the new plugs and have to do the job over again. Just read through some of the GM forums and see what others are saying about using other aftermarket plugs in GM vehicles and how well the Delcos are.
Other ways to increase mileage would be to keep unneccesary items out of the van to keep the extra weight to a minimum. And have the van checked out as soon as possible when your SES light comes on as it usually is an emission related item that needs attention, and faulty emission items can decrease gas mileage. If you have a kuggage rack use it sparingly as extra items on the top are not very aerodynamic and cause resistance while driving,further lowering your m.p.g.

You're not gonna get much better than that. I get 21-22 in everyday driving, 25+ on highway trips (I also own a '99 Venture). I think the last brand new one I looked at listed 19 as city mileage, and I'm not sure what the highway rating was.