Same problem with my 2001. When it clicks I can look under the cap and see the o-ring clearly not sealing to the neck (not even close to sealed).

I have to pinch the sides of the gas cap together while I tighten it to get it to seal. I thought it was just me that had this problem. I also bought a new cap and thought that maybe I got a bad cap or the wrong one and was getting ready to order another, but it seems to be a VERY common problem.

Rover gods have struck again!:mad:

I used this kit to add the tether strap back to my replacement gas cap. I did not use the ring supplied. Just drilled a hole in the top center and put the push-connector in the hole. I had to wollow out the hole a little at a time to get it just the right size.

2004 disco gas cap backs out
 

That's what's happening with mine. Just a couple days ago I filled up. Drove 80 miles and today cap is only on by a couple threads causing the ses light to come on. Again. Seriously. Is there an actual "fix" for this???

Buy this. No more problems.

http://cgi.ebay.com/ws/eBayISAPI.dll...m=221529343062

I have a Stant aftermarket cap installed due to the fitment problems with the fuel neck discussed here, but I wonder if it has the same venting properties as the OEM cap? My SES light still comes on occasionally and I suspect the aftermarket cap may not be venting the fuel system at the same rate? Thoughts?

Do you have an ultragauge or something you can check the code? Mine hasn't thrown the p0455 code since I got the Stant cap.

No Ultragauge. I have the EasyOBDII program running on my notebook PC that gives me basic info on codes currently stored, ready for test status, and of course lets me reset my SES.

Current code is P0455 Fuel/Evap System System Leak (Gross)

This is with my Stant cap installed and tight. No other fuel system problems exist on this vehicle to my knowledge.