now getting code P0488...?

[F-127]

I'm going to say that it's a coincedence that the code came on with the rollback and FICM reprogramming. The code basically means that the commanded EGR throttle plate isn't jiving with the actual(or 'sensed' rather) EGR throttle plate position. If I was you, I would check to see if there is actually a throttle plate in the intake horn. If there is, I would find either a dummy intake horn without the throttle plate or a 05-07 intake horn. Is this throwing a soft code, not setting the light in the dash but detectable with the insight or scanner... or a 'hard code', setting the 'check engine' light in the dash?

P0488
Condition/Description
EGR Throttle Position Control Range/Performance
Fault trigger/Comments
Checks for a difference in commanded and actual EGRTP
Probable Cause
Fault sets when the difference between EGRTP and commanded
EGRTP exceeds the limit for a specified time