After lot’s of knitting with the memory (Teensy3.1) the setting of needles was becoming heavy, difficult, impossible.

Problem: putting oil in the solenoids casing.
Solution: WD40, spraying in this casing.

Problem resulting from the needles getting more and more difficult:
the setting of the needle, pushing it down at the right moment was lost.
The carriage was pushed up.
Solution: see post about callibrating the solenoid position.