I had that problem on my old Roadster ( 2005 ). I had to replace the filler hose. It had a smaller vent pipe tee'd off, going to the vent connection. The original hose had the smaller pipe left full length, resulting in a loop which formed an air lock. I cut the new one down so that there was a fall all the way to the tank & from that day on, it filled at full pump speed. I don't have any problems with the 3.7 Roadster. I notice that the vent pipe now comes from a connection on the filler cap assembly. I'd check that the vent pipe does go down hill all the way to the tank ( & also that it hasn't kinked)
Ian
David, it almost certainly IS the car that's at fault. I too had this problem - 2005 4/4 - but the filler hose perished and when I replaced it I cut the vent hose to the correct length - no problems since. Take out your spare tyre (if there is one - will be difficult if you have a flat back panel!) and look at the hose - the smaller vent hose comes off at right angles and should run towards the left, without a pronounced bend, downwards to the vent on top of the tank. If it's too long, undo the clamp and re-cut to length (a Stanley knife does it nicely). No smoking of course!
I'm visiting the factory in May, so will look at cars being built to see if this is an original "feature"!
Nigel
Nigel
