Car not running properly

[Josez45]

I have 1984 528e which I recently switched out the old ecu for a 1987 green label in order to add a turner performance chip. After adding the new chip and ecu the car ran fine for a while until I floored the car to 60 mph. After flooring the car, everytime I came to a stop and tried to get the car going again it would hesitate and almost stall out but kept going eventually. This was until I came to another stop and after hitting the gas the car died out and I had to push it off to the side. With the car now in my driveway it turns on fine and still has the same old searching idle it allways had but still hesitates and stalls when gas is given but only on low rpm. I tried reinstalling the old ecu but it had the same issue. I have currently replaced the intake boot crank case breather hose, and one of coolant temperature sensors. The car is also running on 93 octane as turner recommends but it was from a sketchy loves gas station I've never been to. Any suggestions on what could be causing the car to hesitate and almost stall out or in some cases actually stall out completely.

[Galahad]

swap back to the old ecu, see what happens