Toeknee here, I have reading the different areas of this site and have found a TON of useful information! Thanks to all that reply AFTER they have solved problems, that really helps.

I have been searching for issues on the 6.4 about going into rough idle at 650 RPM. I was getting the error code P2199 IAT 1/2 correlation. This model has the combo MAF/IAT just after the filter. All of the readings seemed to be in a good range, so I change the IAT2, much cheaper. Did not resolve the issue so bought the expensive combo. It made the P2199 code go away and now throws P0101.
With the OBD Fusion app, I can watch the MAF jump all over at idle 3-5 range and then it goes into super rough idle and green wrench light comes on. If I hold the throttle at 750-1000 RPM, it stays in a good range of 10. Runs great other than idle. Any pointers for a newbie?
Thanks!

 

The IAT2 was completely carbon coated as another post said that fixed their problem, why I replaced it. The MAP next to it was completely plugged also, so it was replaced. After a warm up test run, I am now back to P2199 code 1/2 correlation at idle... Seems like it is being chocked out and not getting enough air at idle. Ugh
Toeknee

 

Thanks for joining it's great to have you here
Tony

 

Thanks!
The 6.4 Powerstroke seems to be one complex and temperamental engine from all the posts I have read. I am still struggling with this idle issue, not sure if I put it in the right forum?