[John Rogers]

For the throttle, the way I always tested it was to disconnect the cable at the engine and have some one move the pedal and feel how the resistance is. Test the throttle body to make sure it is free. If not real free then disconnect the cable connector at the pedal cluster and make sure the cable slides smoothly, again taking two people. Finally feel how the rod and pivot feel and I would bet that is where the friction and stiffness is.

For the exhaust, did you disconnect the muffler before doing the exhaust to head joint and also make sure there were no gaskets left in there? I always did the exhaust to heat joint w/o the rear part of the exhaust connected, started the engine and let things get hot and then retorque the nuts to the correct torque setting. You did use the correct torque for the nuts?