While driving my 2013 XKR in the Blue Ridge mountains, I received a "Restricted Performance" error message, car lost power, when trying to apply power tach would rev to about 3000 RPM but car would hardly pull. Took car into Jaguar and they could not find a code stored. Anyone had a this problem or could shed any light on what might have caused this? TIA.

 

texasxkr,
I had it happen about 3 weeks ago. The first time it was momentary and I did not lose power. Second, third, and fourth times I lost power as well and the restricted performance warning stayed on much longer. It turned out to be the water pump for the supercharger was malfunctioning and when it does it protects the supercharger from overheating by keeping revs down and essentially turning off the supercharger. I had the supercharger water pump replaced and haven't had any repeats in the past 2 weeks.

 

That's occasionally been reported as the fix for the STR, too.

(In effect the car sees IAT2 as hotter than expected so pulls timing etc - sometimes manages to flag a code but may take a few drives.)

Even a bad battery can cause RP. It's the car trying to allow continued use despite being in distress. It tries to flag codes but if enough things look weird or if the code(s) need (by law) 2 similar occurrences it struggles.