307cc 1.6 petrol antipollution?

Anti pollution light came on car jerked all over the place needed 5000 revs just to get it moving, read all the posts which are a mine field. Called out the old AA. He plugged in his computer and narrowed it Down to coil. He removed all the errors so diagnostic and code removal cost me nothing. Picked up coil and set of plugs from local parts store, fitted em within 20 mins and car runs like a Ferrari (touch wood) stuck some Catclean in for good measure and so far no problems. Parts cost less than £100. Happy days