The black plastic thing on the side of the FPR. It's leaking fuel for some reason, also where can I pick one up?

 

You mean this?

It's only function is to tell if your fuel filter is clogged. It is dealer only. I just put a 1/8 in pipe plug in it. Change your filter every 15k and you don't need the sensor anyway.

 

Good deal, I noticed yours has a wire on it in the pic, mine isn't there,oh well it's gone tommorrow.

 

Put some teflon tape on it. Leave the first few threads uncovered. Don't overtighten it and you'll be set.

 

I had to replace mine a while back. It was not leaking at the threads, it was leaking internally and coming out of the wire terminal. Easy, quick, and cheap. I would just put a new one on if you can find the part.
You probably have a loose wire dangling down there somewhere.

 

I have had to replace 2 of them, (different trucks), and one was not hooked up. I had to look for the wire. They were a bit expensive. I would just use a plug like 61 uni said.

 

Seems most leak as you state.
The sensor spends most of its time under pressure.
Its a vac sensor.
I have just cut one apart to see why the failures.
Looks to be the ULSD is suspect.

Bill