long time no chat dennis :)
for a fuel additive, try a small percentage of isopropyl alcohol in a full
tank of gas
as for the ecu, i have no clue...
have you tried convincing the insurance company that your van is diesel
powered? (no smogtest yet in md)
anyways, good luck.

-sudhir (1984 Vanagon Z34 :: 1996 Jetta Trek)