hey i have a 04 sunfire i just got it and it has 10,000 miles on it last night i was driving and i was in 3rd gear. I let off the gas and it like yanked back and forth real hard ide only be at 2-3 grand. So i shifted and it backfired real bad after all this it would keep doing it so i pulled over shut the car off and start it back up and it would be fine i just wanna no if anyone every experienced this b4

anything its kinda getting worse