Not normal. I haven't read the older thread recently - what oiling have you done on the machine? Pfaff machines are German built - way tighter tolerances than say a Singer of the same age. They need to be oiled religiously or they're more prone to seize up - or slow down at least. The 1222s that I've serviced purr like kittens - only the IDT is a little noisy.
The other thing is even a balanced stitch if the tension is too tight both top and bottom can make a machine noisy and hard to start.