The car had been misfiring. Ran the codes, cyclinder 2&4. Replaced all the plugs and all the coils on all cyclinders just to be safe. Car ran fine for a week. Did the same thing. Started chugging on take off and idle. It's really bad when you get up to 70 on the highway. Checked codes. Cylinder 1 misfire. Now the check engine light is off but it's still running like a misfire. What else could it be?? Any help would be appreciated.