I have a 97 JXR supercharger Jaguar. I love everything about the car. However, as the weather cooled the car started to randomely cut out. The car will start right back up, and I can keep it going by giving it gas and holding my foot on the brake. The issue did seem to begin when the weather dropped below 32 degrees overnight. Of course, with the colder temps, I ran the heat. That may have been a vaccuum issue. I did have the valve replaced (a recalled part) and the lines cleared.
I have also noticed a possible gasoline issue. I was purchasing lowe octaine gas at times. That may have caused the issue. I have only been purchasing higher octaine gas at better reputable stations of late and the car seems to run great.
So, could the lower poorer gas have caused the issue? If so, what is the best octaine to purchase and what brands? Also, is the Shell v-power gasoline safe for my engine? Is the Exxon gasoline safe ( with the additives?)