A bad batch of fuel has been verified in Hobart.
Regular 91 octane unleaded sold at BP Lindisfarne last week came under suspicion when cars began running rough or even shutting down altogether.
Initially, it was thought some diesel might have infiltrated the petrol.
After testing by BP, the company has now admitted fuel sold at the Lindisfarne outlet was what it calls off specification likely due to an incorrect delivery.
BP Premium 95 and Ultimate 98 were unaffected.
Those impacted with a fuel receipt and a mechanic's assessment can make a claim for compensation.