I'm a new S type owner ...2003 V8 S type 60,000 miles had the vehicle 2 weeks When I start the car after sitting overnight and I drive it first thing in the morning I get a weird slight surging and leveling out during a 30-40 mph range no check engine light or anything comes up...if I accelerate up to 60 mph goes like a rocket after about 4-5 miles it entirely disappears and the car drives like normal for the rest of the day. No vibration no other noise...any suggestions or help would greatly be appreciated I don't live near a Jag dealer.

 

 
mine does it too , seems to be common . it may or may not be cured by a trans reflash
.
you can find all the TSB's at the top of the s type forum . mine has been reflashed twice by the previous owner with no luck . i don't care just select 4th gear un till its warmed up . takes 5 min. i have read some have cured it via replacing the torque converter . when the reflash fails . I've also tried new fluid and pan/filter still does it .
good luck with your reflash .

anyway this is the TSB blow .
S307-14
TECHNICAL BULLETIN


12/2003


Subject
Surge During Warm up at 40mph to 60mph

Model: S-TYPE Vehicles N/A
Year: 2002.5 to 2004 VIN M45255 to N01600
Model: S-TYPE Vehicles SC
Year: 2002.5 Onwards VIN M45255 Onwards
Section: 307-01 Automatic Transmission/Transaxle

Summary
S307-14: This Technical Bulletin has been issued to address a customer concern of a surge in excess of 150rpm during engine warm up, at a temperature of 30°C to 50°C and at a vehicle speed in the region of 40mph (64.3kph) to 60mph (96.5kph).

Action
Should a customer express a concern, the Transmission Control Module (TCM) should be re- configured using the Worldwide Diagnostic System (WDS) with software release JTP 759/27 or later. Follow the workshop procedure outlined below.
Note: Due to some homologation laws this action will need to be monitored. For this reason a new coded access route will be available on WDS for this Technical Bulletin.
Workshop Procedure
1 Position WDS alongside vehicle, switch Portable Test Unit (PTU) 'ON' and allow software to load.
Note: Ensure WDS is loaded with software release JTP 759/27 or later.
2 Connect PTU to vehicle using diagnostic cable.
3 Enter vehicle VIN and navigate to configuration main menu.
4 Navigate through the configuration of existing TCM application to screen that states 'Select the
access route you require for this vehicle'
Note: When carrying out this Technical Bulletin only, select the 'Coded Access' route.
5 Record the ten digit request code displayed on the PTU screen, then continue to the next screen.
6 Contact Dealer Technical Support (DTS) to obtain the ten digit access code.
Note: You will need to inform DTS of the dealer details, the request code and details of the vehicle.
7 Enter the ten digit access code and continue through the application following on screen prompts.
8 After re-configuration of TCM is complete, switch 'OFF' PTU, disconnect from vehicle and return WDS to original location.
JSB-12/03-S307-14-EN Page 1 of 2
S307-14
Warranty Information

Description
Vehicle
SRO
Labor Time Allowance


Causal Part
Re-configure TCM through coded access route


 

A softwear issue and my V6 does the same slight surging when not fully warmed up between 40 and 50mph. Doesn't do it when hot.

 

Thanks so much for the info and reply Datsports much appreciated I will just monitor it for the time being.....