Hoping someone can give me a clue... for some months my 84 XJS V12 HE had been starting with a very rough idle and frequent stalling (requiring some pumping on the accelerator pedal to keep it running) when the car was left sitting a couple of days; it would smooth out after 2 or 3 minutes as it warmed up, but I really gave the starter (and my right leg) a workout doing all those restarts. Once it smoothed out, it was fine and ran and started strong the rest of the day, and would usually start OK (albeit just a bit weakly) the next day. Left overnight at the shop several times, the car started OK for the mechanic (or so he said).
I just returned from an extended trip and could not get past the initial rough idle when I tried to use the car today. Starter cranks fine and it will fire weakly when the key is turned, but it stumbles very badly and seems to be hitting on only a cylinder or two, necessitating rapid pumping of the accelerator pedal... it will immediately stall if the pumping is slowed or ceased. I was not able to get it to smooth out, my foot and leg gave out from pumping, and I had to take a break to recharge the battery at one point, but the engine never did get beyond the coughing and stumbling stage.
Fuel pump? Fuel filter? Ignition? Some sensor or other gone bad?
Anybody else run into this problem?
WayneC