2000 Xlt
It's got a cap, and a funky looking wooden contraption surrounding an auxilary fuel tank in the bed. What size is the standard tank, and why would someone eliminate 1/5 of their bed for this tank?
Thanks for taking the time to help out a stoopid newbie!
The 2000 PSD is the 7.3 L not the 6.0. I'm going to move/copy this thread to the 7.3 L forum where hopefully you'll get more comments.
But, welcome to the 6.0 forum anyway - and to FTE. Please take a moment to check out the Welcome sticky post at the top of the 6.0 L forum page as well as the other stickies there. Lots of links to great threads and other information. The search feature works great too

And for your viewing pleasure, check out the link to the Posting and You public service announcement:
http://www.albinoblacksheep.com/flash/posting.php


