97 Bonneville front end vibration

[bdahl]

Can anyone offer some advice? My 97 Bonneville SE has developed a front end vibration/shake between 90 and 110 kms/hr. The engine light came on during a recent rip and the mechanic shop retreived the code as a transmission problem. I took the car to a transmission shop and they ran some diagnostics and told me the torque converter was slipping in and out of lock-out and will have to be re-built. I have read other threads in this forum which suggest it could be something as simple as replacing the coil pack. This symptom gets worse when driving against a strong wind or when the engine is under load.
Has anyone had this problem and has anyone actually found out what causes this vibration. I have changed tires and balanced them twice and even had an alignment done and this does not help.

[maxwedge]

A full scan with a trans capable scanner in the right hands will show if the tcc is slipping or disengaging, a bad tps can cause this, valve body problems, solenoid problems also. If this a part checks ok, yes a mis fire can mock tcc symptoms, and should set a code. Posting the copde would help here, also.