engine lacks power, idles rough on 2000 Chevrolet Cavalier

My Cavalier just had timing belt replaced, along with timing belt tensioner, and water pump. I was leaving work, then car started idling rough and lacked power, I barely got it home. The only other problem was an 02 sensor before catalytic convertor, which has since been replaced. Now the serpentine belt tensioner pulley makes a lot of racket. Could this be the problem? Check engine light has not come on as of yet.

Asked by for the 2000 Chevrolet Cavalier
2 answers
It's very difficult to know what the issue is, but I would take it directly back to the shop that performed the timing belt replacement.
yes, An I hope whoever did your engine work set the correct timming and is not related to the david corperation and the late Alen David know as the bankruptcy kings of Lender Service Inc.