One more update, and finally closure:
Well, turns out we were not done with this tire. After my last posting, I continued to watch the tire, and unfortunately, it continued to leak air. It actually seemed to get worse - got to where it was losing 'bout 4 or 5 psi a day, since last posting.
Since I had the Motorhome at the Ford dealer this last week, anyway, to have them take care of a warranty issue with the AC compressor, I told them to have a look at the tire, see what they could find. I should have gone there from the get-go! This Ford dealer is a large one, the only one around here that can handle big rigs like this (Crossroads Ford in Shelby, NC). They seemed to have quite a bit of expertise in dealing with tires like this.
Anyway, they indeed found a leak - a 1/4" long cut from some kind of road debris (have no idea what). Was unnoticeable until they put the tire in a submersion pool they have, and even then, had to watch very closely, as a bubble would only come up every now and then. That is why the other place never found it.
Here's the really unfortunate part - The cut is right up against the sidewall, they cannot repair or patch it. Arrrgh! :(
Sooo, today, with several hundred $$ less in the bank account, the MH is finally back home, ready to hit the road, with a new inner dual tire that FINALLY does not leak. Also has a new AC compressor (dash AC), as old one was leaking oil (fortunately that part, Ford picked up the tab under warranty).
I kept the old tire (its in the garage). They marked very clearly where the cut is. I took a picture of it, too, that I think I'm going to try and post here later. If I can find someone willing to patch/repair it, I just might keep it as a spare. If not, the Ford dealer agreed to take it back and dispose of it properly for us.
Really, really hate to have to shell out this much $$ to replace a tire that was barely 3 years old, but at least now we know this problem is solved, and we can focus on more fun things, like getting back on the road, camping. :)
Anyway, sorry to dredge this topic back up, but I wanted to let everyone know what the true, final result from this was.
