At light throttle going 25 mph or 30 the rpms go back and forth from about 1400 to 1500. It's annoying but it disappears at faster speeds.

There was a thread about this a couple years ago but I can't find it.

Is it the tranny locking up and unlocking? A dirty throttle body?

TIA. Norm

2003 XK8 Convertible 105k miles

 

nothing ever absolutely has been confirmed that I have read, typically it is a bit of slippage in the torque converter...new fluid might resolve it for a while, a new tq will probably solve the issue, a rebuilt tranny will probably...etc, etc.
The fluid change should probably be the 1st step. In my case I drive it in 3 until warmed up and then when placed in D everything was fine.
wj

 

For 03-06 6 speed, is the ATF change at 50-60k a must do like the 5 speed? Also my 03 doesn't surge but makes a slight noise ("chirp") shifting from 5 to 6. Local indy said Jag recommends adding a 1 quart of something designed to improve solve the problem. Good idea? Would this also help the surging being discussed?