2006 Dodge RAM 1500 Big Horn 4.7 (not flex) has rough idle?

Ok, so I started with a P2098 (post catalyst fuel trim bank 2 system too lean) error code. I've been sure not to use garbage gas and I always get it from the same place. I even go so far as to use the gas treatment and fuel injector cleaner every few months, but nevertheless I replaced all the O2 sensors with OEM Mopars. But, even before getting this error, I noticed that I started getting poor MPG (dropped from about 16.5 down to around 14.5 with no change in driving habits) and I started noticing a rougher idle than normal when stopped at a red light. It drops to around 500 RPMs, which most will say is about right, BUT, my truck shakes a bit more than friends who own a Dodge RAM. At first I thought the PCM needed adjusted but I have been told they don't lose their timing unless there is power failure. Other than the rough idle my truck runs very smooth and has great get up when I accelerate (even more than the friend's truck who has a smooth idle) so I'm not sure if I truly have a problem or not. Here is a list of what I have done so far and I am stumped as to what else it could be:

1. Cleaned my washable/reusable air filter (as I have done before)

2. Cleaned the airbox

3. Used CRC MAF Cleaner on the MAF

4. Cleaned the throttle body

5. Replaced IAC

6. Replaced TPS

7. Replaced all spark plugs with OEM (gapped properly)

8. Replaced the fuel pressure sensor

I have about 88k miles on it and other than the rough idle I have no complaints. Any thoughts or ideas?