Problem with car
 

coworker has a 2008 135i, manual tranny.

when he shifts, from say 2-3 (happens with other gears as well), and gives gas right after shifting, the car kind of jolts and seems like it's struggling to gain power. doesn't happen all the time.

dealership isn't sure what's happening. could a problem with the catalytic converter effect this?

thanks!

I wonder if it's just Drive-by-wire throttle issues?