My van is loosing power, will not go over 15-20 mph

There are many variables that affect vehicular performance. Reduced engine power could result from something as simple as an Air Filter, or something more expensive such as a computer issue. There are also situations where a fuel issue could limit your speed, or a Mass Air Flow sensor. I would recommend having the codes swept at an automotive parts store, as they will typically do this for free, and then search the internet for more information related to the Diagnostic Trouble Code that they give you. Good luck!

This happened to me twice now. All I had to do is go (slowly) to the local COSTCO and fill up and it worked fine. I think it's a low fuel sensor. But this time I think my fuel was freezing because it was 17 degrees last night. I filled up and went on my way.