Had mine handed back today after a new ECM, now runs like a dog! Fuelling issues right throughout the Rev range and at any gear, bike sags and jerks. In fact the only time it doesn't is under brisk acceleration. As soon as you throttle off or try to hold at constant revs, which is typically at the throttle on / throttle off point, fuel transport time lag makes it impossible to ride properly.
Don't put to much faith in the new ECM, check out TPS and after market fuel controllers as well.
Me I'm dumping the bike as a lemon and looking into alternate brands, after I given Suzuki GB a dressing down.
You can't answer this, but I wonder what tests the shop did in replacing the ECU other than the obvious of pulling the plugs out and sticking them back in the new ECU unit? Bet nothing from how your bike is reacting to the change.
I have searched my Gladius W/Manual for this task, but there is nothing listed. I have read all the too and throw of throttle maintenance and repairs, and the common ending is in 'resetting the ISC Learned Value".
ISC is Idle Speed Control.
As the secondary butterfly in the throttle body is closed when the bike is coasting or parked with the engine running, the ECU's STVA driven top butterfly (Suzi calls a butterfly a Valve) no air can get into the motor and the motor would stop.
But there is an air entry route around the Closed butterfly through a cut out in the butterflies spindle (the spindle is D shaped).
With the Suzuki or Heathtech etc tool, this value and 2 other throttle body learned values need to be reset to a 'learned value' in the ECU's memory and presumably has an influence of the air mixture mapping.
I am purely speculating (I am not a Bike Mech.) that that your new ECU has no useful value or some random value. I would assume the Factory flushes old test results and would load good values for the bike to run, but I wonder if they are spot on enough for you particular bike without fine tuning via the Service Tool.
Of course, the new ECU could just be stuffed too or the Battery terminals were left loose.