I have a 1992 xjs with the v12. I steered driving it once the weather got nice around April. It ran fine for a while and then it was hard to start after it ran a while. Once it cooled down it was fine. Eventually it started to feel like the engine was misfiring and then it would barely stay running. I was able to limp it home. I can feel the exhaust nice and even from the passenger side exhaust pipe. The driver side sputters tremendously. I don't know where to start checking for problems. There are no obvious cracks in the pipes or hoses and everything seems to appear normal, meaning there are no obvious signs of problems. I am getting the ff36 fault code. Any help would be greatly appreciated.

 

This is a Marelli car. Most likely, you have a amp, or a coil giving up. I would start by pulling the distributor cap, and giving the rotor a good look. They seem to be the weak link in the Marelli cars, especially if it hasn't been changed in 30K miles. Seems plug gap is very critical. As the wear on the plug occurs, the gap widens, making the spark between the ring inside the distributor and rotor hotter. Checked or changed plugs lately?

 

Thanks for the suggestion. I will try it and keep my fingers crossed. These cars are lucky we love them.