Purrless Jaguar

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?)

Any name brand premium gas is safe. Your problem sounds more like something wrong with the cold engine mixture, possibly a bad sensor, injector, maybe a broken/loose vacuum line or fitting. You’ll need a good Jag mechanic to sort this out, I’d think.

Ditto to what Texases said. I’ll add that your Jag has an OBDII diagnostic system and you might try having a parts store download the codes if there are any and post them here. Jag was a Ford product in '97, so there should not be a problem getting the codes read.