1998 Pontiac Grand Prix chugging engine

Engine problem
1998 Pontiac Grand Prix 6 cyl 189000 miles

I went on a short neighborhood trip, mabey 3-4 miles before this happened with no problems. Then about 3-4 hours later when my husband and I went to go some where else We had come to a stop sign not 500 ft from our drive way, went to take off and it totally lost power. It didn't shut off just lost power for a few seconds. Then it started slowly picking up some speed but was chugging while doing so. Thats when the check engine light came on flashing on the dashboard. I know this car has alot of miles on it but litterally not 3 hours previous to this the car was perfectly fine. Anyone have any suggestions as to what it might be? I would like to go to the shop with at least some possiblities in my mind so that I will know if the mechanic is trying to inflate his bill with un-nessesary repairs. Thank you.