check engine to chassis earth lead for good clean connections, also check main starter feed from battery to make sure connection lugs/eyes are also tightly crimped and good clean connections. you dont say what vehicle but have heater plugs or any other cold start device been checked and ruled out.is battery correct spec for your van [being diesel] and has it a high CCA rating. just another point is engine oil the correct spec,if too thick can create a high drag till warmed up!
k, March 2011
