well here we go 167,000 miles 15,000 on veg oil it started of with a loping idle while in gear at a red light.it got worse to the point of having to keep my foot on the gas to avoid stalling.then came the problem of hard starts. i would have to crank it for a good 20-25 seconds to get it to start.......now it dosent start i changed the fuel filter and nothing then i changed the lift pump and still nothing.i cant get any fuel i checked filters in tank and on the fuel heater.one major question i have is does the fuel shutoff solenoid shut fuel off before the filter or after the filter.

 

The shutoff is after the filter and is part of the injection pump.

I would pull an injector or two and see if the vegie oil has coked the tips up.