Several people claim that tests found diesel in their engines despite the fact they used an unleaded pump.
Drivers from across the country - including Barnstaple - have also complained about losing power after filling up.
One reader said their son was facing repairs of more than £600 after filling up at an Asda store in Swindon, Wiltshire. Asda has been approached for comment
DevonLive.com previously reported that a Tesco spokesman confirmed on December 18 that there had been a number of car breakdowns at one of its Devon petrol stations and said it had closed the site for investigation.
Read more: http://www.devonlive.com/news/devon-news/victims-supermarket-fuel-fiasco-warn-988534