Did you check to see if your throttle was opening all the way? I have some problems with my kickdown as well, you've probably read my post. Before I had the problem in my post it didn't work at all. Turns out my throttle wasn't opening all the way. What I read is that its quite common for the pedal linkage to bend from people mashing it to the floor for almost 40 years. Or it hits carpet or floor mats. My pedal was hitting the floor before the throttle opened all the way. A quick bend to the pedal linkage under the dash fixed that. May not be your problem but its quick to check withsome help.