Well good news so far.
My wife and I have been plagued with P1121 & P1122 DTC fault codes (limp mode) on and off for the last few weeks before I sent the throttle body out to ASI in Tenn for a rebuild.

I am very happy with the way that ASI responed with a expedited effort to get the rebuild work completed and available for shipping within 6 hours of receiving the throttle body at their facility.

The reinstall of the throttle body was just plug and play.

No DTC codes after startup. We took a 100 mile round trip yesterday with no issues and no warning messages.

I purchased the ASI (also know as ATE) rebuild service on their EBAY listing# 110890089433 for $325.99 - free shipping (UPS ground to them and back from them) Life Time Warranty. It covers 1999-2003 XJ8 models and 1999-2002 XK8 models.

They also have a EBAY listing for 2000-2003 XJR and 2000-2002 XKR Throttle Body unit rebuild service (listing# 380443798745). Price is $325.50 - Free UPS Ground Shipping, Life Time Warranty.

ASI also provides rebuild and stocks many; ECU's, ECM’s, TCM, Antilock Brake Computers, Controllers & Modules, Air Flow Meters, Throttle Bodies,Digital Speedometer repair & programming, Digital & Analog Climate Controllers, Computers & Modules, Cruise Controllers.

This post is not an advertisement for ASI, I am only providing information that I found about them when I determined that our throttle body needed replacement or a rebuild service.

I am sure there are other rebuild service providers for electronics, but the quality, price and warranty are important factors in choosing one.

Jim Lombardi