The blend door should not be causing weak air from the vents, and a gen I does not have a blend door arm like the gen II does. A sure sign of a stripped gear in the gen I blend door actuator is a constant clicking sound from behind the message center, especially after start up. Have you done the EATC self test? I am guessing you might have a vacuum leak somewhere. Check under the hood where the vacuum line for the EATC goes through the firewall. There is also a check valve behind the right side shock tower that could be stuck or partially clogged. If you have vacuum you might have a bad EATC unit or maybe even a mouse nest somewhere. Start with the self test and go from there.