That should be a good test of the different tire size combinations. Prior to ABS & traction/stability control being added to pretty every car these days, all this probably wouldn't have been a problem in the past.
What you are doing would be a big no-no on an AWD vehicle like my Forester. Running different size tire front & back wouldn't create drivetrain issues on a FWD car, but it may wreak havoc with sensors.
If you don't have problems today, but they reappear when you go back to the 165/65r14 tires you will most likely have your answer. I would suspect large difference in tire size is the problem, but I am just guessing, too.