Renault Kangoo engine cut out.

I posted a prob a fair while back titled "intermitant air in fuel" thanks for the answers for that one, I still have the same problem only I have had a bit opf a chance to wittle down what it might be. When the tank is between 1/2 and 3/4 empty the engine cuts out, if you leave it in gear and carry on rolling it will eventualy fire back up again, for a limited time, then cut out agin, the spells of time between cut outs are random 0.5 miles to 20 miles, seems to clear up when I am not on the motorway, new air and fuel filters fitted, air is getting in to the fuel from some where. I have purchased a basic fault code reader and it dispalys no faults, even though the dashboard lights up like chritmas tree every time the engine stops, is it a crap reader? It ALWAYS happens between 1/2 and 3/4 of a tank could it be sticky fuel gauge sender unit, low pressure pump, crap in tank (tried sucking some fuel out at one point looked perfect), every garage I ring give a different answer. Thank you for any answers. You have been a lot of help. Will.