This started a couple of weeks back. It started with 3 codes, a misfire, bad coil and stuck rich. I have since done a tune up replacing all the spark plugs, the bad coil and even the O2 sensor. It is now at a point where the CEL is not on but it still throws the P2196 with a brand new o2 sensor just installed. I am stumped as what I should be checking for next. It seems to run ok but idle is not as smooth as pre-codes.

The truck is a 2006 XLT. Any suggestions or help is greatly appreciated.

 

I have same problem, I think i have a bad injector, will post when i find out...I swapped injector #1 and #4 but code didnt change, however truck still runs rough...