Scion xD, 2009, 111,000 miles

The car shut off while I was driving a few days back. Didn't throw any codes. Took it in and the mechanic replaced the fuel pump, saying the strainer was plugged with deposits. It immediately began to start rough, almost dying and going down to 250 RPM briefly before coming up to 750. Two codes appeared a few days later: P0455 and P0441.

I took it back in and he re-did the install, thinking it must have just been an o-ring out of place. It started fine, initially. After a few times of turning it off/on, it began to start VERY rough and nearly dies if I put the AC on.

I assume it has a vacuum leak someplace. Any other ideas?

 

Clogged injector? Clogged catalytic converter?