I have a 2011 Mitsubishi Lancer ES, manual. A month and a half ago the check engine light came on with the code stating third cylinder misfire (P0303). Three days ago, the same light came on. This time with P0300, multiple cylinder misfire. Both times I have taken it to the dealership and they have reset the light and told me I was using bad gas. However, I know I am screwing the cap on tight enough (4-5 clicks), and I do not go to off brand gas stations. My owners manual for gas says 87, but the light will only stay off if I use 89. What should I do?
The problem is not about the fuel cap not being tight. It is the quality of the fuel since 89 octane works. Either you are stuck with using 89 octane or you would have to get the dealer to commit to resolving the problem.