Need advice on 2015 Kenworth T680 Cummins ISX15 - DPF Deleted - lost driving power.

Please advise if any driver know what causing a truck to lost drive power when merging from off ramp into Highway as try to increase speed to catch to speed limit ?
Example: I'm merging into highway reaching 45 MPH to 50 MPH my truck would just lost driving power and can not shift, so I'm pulling over onto shoulder and stop. Then start shifting to 3rd or 4th gear and start driving fine until I stop again or sometime it does happen during 65 MPH 67MPh .
When I turn my key into "ON" position my mechanical engine light would flashing 25 times before it went away, but my orange Engine light stay on during engine running.

Thank you all,
X_Knight