BMW Repair: ASC T, speed sensors, wheel speed

Question
Don: The car is a 1996 318is.It came into my shop with the mil lamp set and a complaint of very low power and bogging. I pulled a p0420 and 1174 with my reader. I cleared the codes and took it for a road test. Started out just great, but when the tranny shifted and it hit 3750 on the tach,the ASC light began to flash and it bogged down to about 1250 rpm it then picked up to about 3700 rpm and bogged repeatedly. I stopped the car and pulled the manual to find the flashing symbol. After checking the manual I disengaged the ASC switch and it ran just fine. Whats up? bill 765-362-4409                            Thanks

Answer
P0420 was probably set when(most common reason)by the car running while fueling up.1174 is a fuel trim code.There is nothing adjustable in the ASC system.Are the tires good and matched?That will cause an ASC problems,wheel speed sensors, all the ABS system.The ASC was activated by one of those systems.The 1174 came probably from fuel shut off.