So I wanted to share my experience of check engine light about 6 months after JRSC+CARB+oilcooler install. As subject line says, codes retrieved were P0171 U0073 C1201. The main concern was running lean.
This condition apparently triggered some kind of protection mode which disabled traction controls so the traction control light was on as well.
The end result was a faulty BPV. It's been about a month since replaced bpv, and the car has been running check engine light free!.
JR support and I spent some cycles and went thru number of checks to verify installation correctness prior to replacing bpv.
I referenced the part number and it is indeed a part commonly used on factory SAAB and Audi turbo engines, this confirmed prior posts from JR that the bpv selected is an OEM quality part.
I am glad to report that I had a positive experience with JR providing support to their SC system. I received bpv promptly with fast shipping and shipped back old part with included shipping label. The part was later confirmed to be at fault.
If you see check engine and traction control lights on, check/replace bpv!
The FRS went from somewhat lackluster to now a proper sporty coupe con gusto! All thanks to JRSC
Happy boosting!