You might have a rear end ratio problem. From others posts, the trans goes in to limp after the 4th gear shift if it sees a overall ratio problem. ( 4 th is direct drive )

Try to drive the car in 3rd

Have a look at the trans controller and ABS part numbers / version coding, I'm wondering of someone mix matched parts.

There might be a grounding issue, others have had odd electrical faults.

I have a 97 E320 parts car that goes into limp. When that occurs, the high beam indicator lights up , left fog light turns and some sort of warning pops up on the dash. Haven't tracked it down since it is a parts car.