Well, I spent quality time with the Disco last week and finished fixing everything I found wrong including the leaking fuel tank vent and rotted tank fill hose after taking delivery of it a couple of weeks ago. I filled it up Saturday (NO leaks YEA!!!) but I noticed a LOT of vacuum when I opened the fuel cap for fill. Not a small psssst, we are talking 3 to 5 seconds worth after only a 1.2 mile trip. It ran great all day Saturday and Sunday during our travels so I gave my wife the go ahead to drive it. I'm out of town on business and she called, it left her sit. After an over the phone diagnosis, I had her open the fuel cap, heard the looonnngg his and after a few seconds of cranking she fired up, ran a little rough at start up (through a CEL imediately) but ran fine the rest of her way home. I had her pick up a new cap, but she said there was still vacuum after start up and shut down. Is vacuum normal on these or do I need to look for a blockage in the evap system? The starting after the cap is removed could have been a coincidence since I wasn't there.... She's a good DIY'r, so if anyone has ever expierienced this or has thought's on what I can have her check, it would be appreciated.

 

You need a new gas tank, there was a recall on them, they would not vent properly and the fuel pump would suck all the air out of them and they collapse (its plastic) and then the fuel pump would starve and the engine would run out of gas even though the tank had plenty of fuel left in it.
Write down your VIN# and call a Land Rover dealer and ask them if your truck has the upgraded fuel tank.
If you let it go to long the tank will crack and leak.
You can have your wife leave the gas cap loose until you can get it in to get fixed.
IF you do need a new fuel tank make sure the truck is less than a 1/4 tank when you take it in.

If they will not replace the fuel tank for free for you then have the EVAP system checked out before YOU buy a new gas tank.
Your EVAP canister could just be full too, but have the recall looked into first.

 

Thanks Spike555, someone else a few weeks ago mentioned a fuel tank recall on here when I mentioned my laundry list of items I found needing replacing. When I checked, my VIN wasn't showing up under this recall. I will ask again.

 

I do not know which years the recall covers, but I would call 3 different dealers and if you get the same answer from all three then you know its not the gas tank.
It also affected Range Rover Classics.