any of you guys know if theres a drain plug for the diesel tank I presume its got loads of crap in it as after a few hours driving engine system fault keeps coming on then it wont start and not getting any diesel but if I stick the airline on pipe and blow it back to tank once I reconnect diesel pipe fires straight up replaces the diesel filter a couple of weeks ago and it was great for a week then its back again

No there isn't. What your problem is likely to be is the pick up filter on the bottom of the pump. The bio-growth in the tank gets sucked into the filter, blocking it. No other option but to drop the tank and lift the pump out

is it a easy job before I start I have the use of a 4 post ramp