Our '90 TBI blazer runs great, except that the computer won't let the RPM drop rapidly when the gas pedal is released. This is a real pain with the stick shift (SM465). It makes shifts slower and rougher than normal. Is there a way to correct this? My guess is that this feature is part of the smog control system. The TBI is better than the quadrajet in every way except for this annoying characteristic. Thanks in advance for any help or ideas.