What could be causing my Jag to cut out in the middle of driving on the highway? It happens intermittently. It has always only happened when letting off the accelerator quickly. When it happens, the RPMs start dropping (pressing on the gas pedal doesn’t seem to make a difference), the car lurches a few times, and the engine usually cuts off totally. When it happens and I’m driving down the highway, I’ll put the car in Nuetral quickly (so I’m coasting on the highway at 65mph),and I’ll restart it; it will start right back up, then I can move it back in to Drive, and away I go. Other than this, it drives like a champ. The car first did this this past summer, did it once a month or so, then recently, the frequency has been 1-2 a week.
I’l bet the throttle body is dirty, especially the IAC (Idle Air Controller) port. This can lead to sticking throttle and a slow to react IAC.
Have you found your problem yet ? My 1998 XJ8L just did the same thing today on the Highway first time. Going into the shop tomorrow.
It’s the system that replaced air bags in English cars.