Reduced eng performance
 

09 ssHHR 56kmi 5 spd reduced eng performance warning came on, went into limp home mode using synthetic oil , the warning system was still set to original system , raised hood everything is still hooked up , IDEAS? TERRY

Check Engine Light on ? Even if it isn't, you need to pull the codes. You have one (or more ) that has triggered the reduced power.
Post them up here (numbers only, no descriptions) and we should be able to point you to the problem.

X2, codes please, and how old is that battery?? Original??

I think normally the reduced power problem is 9/10 times related to the throttle body and/or accelerator pedal, no?

Not all the time. OP hasn't provide enough information yet.

CODE P0087 [fuel rail pressure too low?]

Intank fuel pump or regulator

https://www.obd-codes.com/p0087

HPFP? Or is that a different code?

The HPFP could effect rail pressure, I am sure.

So will the fuel pressure regulator and the low pressure pump, I just read the article for the code, it doesn’t mention anything about HPFP