[s-cars] Code 2142 with new MRC chips

[Premier Investment Properties,LLC.]

Hi all
I recently installed a set of MRC chips in my S4 and immediately had the
check engine light come on under load. The car will only accelerate hard one
time and then it seems to go into "Limp" mode, only see 1.2bar on dash gauge
until the car is switched off and then the symptoms repeat. 

I am running 93octane fuel and the car has had recent plugs..

I ran the codes and 2142 is pulling up( 2142 (Blink Fault Code), knock
sensor #1 (G61)
Open or short circuit, Defective sensor Check sensor and wiring
Symptom: Timing retarded, High fuel consumption, power loss, Boost pressure
not attained)

I will check and replace the knock sensor, but wonder if it could be
something else? 

Any help would be appreciated

Tim 

92 S4