Hi:
A few thoughts,....
120/104 cams in a 3.0 or 3.2 are race cams and will not idle nor run well below 4000 with the single-throttle Carrera manifolds. Its an intake reversion problem. To use those cams you must either use carbs or an ITB intake. The most cam one can use with the Carrera intake are 964 or 20/21 ones.
Dyno tuning only maps part & full throttle sections of the fuel and ignition maps. The rest must be done in the car to get the best drivability. Sounds like some further work with the Tec3 is needed for idle control and part throttle timing and fueling.
Your engine configuration is not matched well and I would recommend either a cam change or a different intake system. Further, if you have the early small-port SC heads, the Carrera intake runners are too big (unless port matched) and you are really over-cammed for that setup.
