Is there an egr simulator installed??????
That could be a problem with the EGR delete.
31 is EGR valve position sensor low voltage
84 is EGR Vacuum Regulator - Solenoids
EGR cutoff solenoid - Solenoids
EGR Vent solenoid - Solenoids
Having a malfunctioning or non-working (or non-simulated) EGR can make your car run like crap.
Got any pics of how the egr is delted? Was it deleted usuing the plunger mod?