Thanks projectSHO89. Although we don't have any nice hills nearby I've had the truck in OD keeping the RPM's as low as possible before letting it downshift, and no misfire/sputter/lunging. So perhaps my 2nd spark plug replacement on cylinder 7 took care of that. When I had an obvious misfire months ago it was extremely intermittent (once a month) cruising around 40 mph in OD, low RPM, it would start shaking. When I needed plugs/coils on my 06 it was extremely obvious, consistent miss under hard acceleration. I wasn't having any of that with the 07. The rough idle may not be secondary ignition related like I've thought all along. I'm hopeful the fresh tank of Mobil gas will do the trick, it's one of the few top tier gas retailers around here. We shall see.

My pending P0451 hasn't come back yet, either from the parts swaps or because ambient is finally going up with spring time. But for my own edification, here's a pic of the top of my tank. The only wires going in are that white connector, all others are tubes/hoses. There's nothing that looks like a sensor there, just a connector which I assume is for the fuel pump. I'm stumped on that FTP sensor location, part number, appearance and have googled/ebayed/autozoned the heck out of it.

 

The FTP sensor is elsewhere on the top of the tank or on one of the vapor lines, it is not on the fuel pump module proper.

 

10-4, I'll be having another look if I get the code, thanks again!

 

Found the diagram in the WSM. It's on the vent hose assembly.

 

Just an update on this after all of the messing around with the rough idle for anyone following or who stumbles on it.

I used my Edge Evo to bump the idle up 125 RPM, so instead of idling at 525 RPM I'm at 650 RPM (foot on the brake, in gear, hot idle). This seems to help and gets me out of the 600-625 RPM zone when the AC/defrost are on and the idle was bad enough to drive me crazy sitting in traffic.

I also tried switching oil to 5W30. This also helped to smooth out the idle a bit. I just switched back to 5W20 to make sure it wasn't in my head and do notice the idle to be slightly rougher. Not bad enough to immediately switch back to 5W30, but I'm going to ponder a permanent change to 5W30 on my next oil change. p.s. this is all with a motorcraft filter and motorcraft semi synthetic oil.

One concern I have is that the rough idle is ambient temperature related. So fingers crossed when temps drop in the fall/winter I'm not back at square one. If I am, it might finally be time to do a real vacuum leak test.

 

I find it funny that you say your idle problem is related to ambient temperature...so is mine...or so I think...

Seems to be worse between 60-80 degrees...above and below that its seems fine...

I also switched to 5w-30, then to 10w-30...and Idle is much better...I have not gotten a code since an injector code a few months back...I changed all of the injectors then...

I have looked at the P&ID's on my scanner also...it seems that the barometric pressure is backwards...in that it is lower when the temp is higher, and higher when the temps are lower (I realize that high pressure doesn't mean high temps) but you can infer that it runs smooth when its nice and warm, and the baro is lower according to the p&id, and rough when the temps are lower and the weather not so nice (baro higher according to the p&id's)...