My 1992 jagurar is puttering and backfiring but only after driving it for about five miles but mostly after putting in gas i used regular unleaded but am now using premium it starts to slow down and will not accelerate to the point it shuts off when i get down on the pedal but i can shut it off for a minute and it will drive fine for a while

Cars & Trucks - Jaguar - XJ6 - 1993 Jaguar XJ6