I don't know how the lockup converter works but I can offer some advice on
the cruise control. Is it not engaging at all, or is it suffering some other
issue? Check the switch on the brake pedal to make sure it works. The manual
transmission version of these cars uses a vacuum switch, I don't recall
whether the auto setup is the same. If it's vacuum, check for cracks in the
hose to it. Also check the vacuum line to the servo on the throttle and the
servo diaphragm itself. The electrical portion of the cruise control is
normally pretty reliable, most of the problems I've come across involve the
vacuum portion. It's worth checking the fuses too to make sure none of them
have failed.