renault clio r 172
i filled up with tesco 99ron for the first time normally use 95ron from shell or morrisons was ok for about 10 miles then went to go into to 5 gear and just went all lumpy and lost power then toxic light came on got it home and it stayed on and sounded like it was miss firing and spluttering from the back box. went to drive to garage the other day and was still doing and light was still on then changed into 3rd and it just come back to life light stayed on thoe decided to leave it and see how it went light went off after about 20 miles. driving it yesterday and it started misfiring again and light started flashing again but stop again on way home and all running normall again and no light but really lumpy on tick over could it be bad fuel as i have heard tesco fuel is crap thanx.