Idle Issue
 

I am new here. I have a 2014 Mini Cooper Countryman ALL4 (R60). I replaced the thermostat housing and cross over pipe. When I did it I disconnected the NEGATIVE battery and the three wiring harness. I put everything back together but when i start the car it idle like it's misfiring and in LIMP mode.

Anyone here had this issue before? Do I need to do something with ECU? I read something about it when you install a brand new car battery.

Thank you for any help!
Roland