I have a 1997 XJ6. I just recently got the fuel pump changed and I also did an oil change with the recommmended oil 10W-30. My car now stutters upon rapid acceleration, but doesnt have an issue accelerating. It only stutters when at idle rpms and when accelerating initially. The RPM for parked is around 900 while when in Drive they drop to abouti 600-700. This issue only started to occur after the fuel pump was changed. I did some research and suspected that maybe there is air in the fuel lines perhaps? I also plan to change the air filts, clean the mass air flow sensor, and eventually get to the throttle body. Somebody also said that the spark plugs might need a changing. I would appreciate any info and help in regards to the stutter.