The problem is after about 15 minutes of driving the rpms go crazy and the van starts hesitating. After I turn it off it won=B4t start up again. The next day it starts up just fine and again after about 15 min. the same problem occurs. And today it wouldn=B4t start up, it doesn=B4t turn over.Mecanic says its the control unit (Digifant)? I=B4m down in Mexico and don=B4t think the mecanics have experience with this sort of engine. Any suggestions of what could be wrong? Help