jumpy idling

[japimport]

hi there got a new exhaust put on my c200 sport today and the car just isnt right the idling is upand down when idle its like it wants to cut out do yous think the garage that done the exhaust could of done something coz it was never like that before thanks for taking the time to read this thanks thomas

 

[Ellsy Tanners]

Have correctly exchanged the o2 sensors and pluged them in?