check engine light is on the code is po420.

http://www.obd-codes.com/p0420<copy and paste the link,read.

The error code is for Catalytic Converter in-efficient, this code does not cause the car to stall or drive in a jerky motion as you have described. However, if the CAT is clogged that would cause the hesitation when trying to go above 60MPH. If that is the situation you will need to replace the Cat. Conv. You should get a professional to do further diagnosis and then a repair.