I can only tell you that I have a vanagon that sat for about 3 years.It
wouldnt start because of gunked up injectors.The PO maintained it very
poorly,so the injectors were probably not clean before it sat.Soooo,dump in
a couple of bottles of injector cleaner and clean them out good.Maybe then
drain out the gas and run it till it stops,like a lawn mower being stored
for winter.New oil too,just before storage.Good luck Gilligan.