I attached the mityvac hose to the line that exits the primer pump assembly (transparent brown line) and pumped (sucked) with the mityvac. It has various attachments to stick into varying hoses. at present the transparent line (the one on the left of the assembly in picture above) is actually spliced with a section of rubber fuel line for whatever reason. I think the mechanics who installed our greasecar veg oil system did that. It loops up then down again to another banjo bolt on the IP. So what I did is simply undo one side of the rubber fuel line and sucked with the mityvac. so the fuel is coming directly from the primer pump assembly. Not through the IP
or anything else.

I dont think we have fastlanes here up in Canada. Napa perhaps? And do you mean 'perhaps but unlikely' that its a stuck valve? or that the resistance is normal? Is it a complicated part to take apart and reassemble? (i.e little springs firing out everywhere or something)

Great, so do I need to remove all the lines and the primer pump to access the 3 bolts? and do you think the problem would be anymore diagnisoble by a visual inspection by removing it?

Thanks Ill do that