Hesitation at 60 mph and up

There are a number of problems that can cause the problem that you describe. It will take a series of checks to start to elimnate some of the possible causes and figure out the problem. Do you have some tools and are you willing to do some tests? If not, then it is probably time to take the car abck to the mechanic. If you can do some tests and are willing to report your results, then maybe you can be hlepd by the people here.

It sounds like from your information that the stalling problem has come and gone. Is that right?

Do you know which hose was disconnected, and was it left disconneted? Do you have any pictures to show? If it is still disconnected, can you tell us if it plugged up or blocked by anything? Or is the end that is disconnected left open?