As for your ECU code 71. I got mine fixed. ECU code 71 is tripped about 1~4 minutes after getting on the highway and at ~60mph on the highway with AC on. The problem was with the EGR modulator, it had blockage. I simple test to perform and check the modulator is to plug portP and portR(bottom of the modulator) with your fingers and blow air through portQ. It will take an effort but you should hear air hissing from the bottom of the modulator cap. If you can't hear air hissing or you shake it and only hear a little bit shake it again and no air hissing, then your modulator is bad.
I replaced mine last week and I have run 140 highway miles and more more ECU code 71.
BTW, have you been at BPU for at least a year and you don't have a fuel controller? I was just wondering if the rich A/F is accelarating the blockage of the EGR system.