Van does not want to start. Replaced battery, and it worked for a few days. Now it won't start, though it sounds like it is going to.

There could be a whole load of issues here.

1) make sure the battery has good charge.
2) check the HT, plugs, coil, all good and clean connections.
3) check the fly wheel sensor is good and clean.
4) check the water temperature sensor is good and clean.
5) check the fuel filter is clean.
6) check the fuel pumps works.
7) check the cam belt hasn't broken.