How do you properly test for a bad solenoid?
If you remove the core from the solenoid it will measure the same resistance but won't behave the same. The moving plunger could be gunked up and sticky. A return spring could wear out or come off. 

But if the solenoid looks okay mechanically and the resistance measures okay, it's probably okay. 

Note that it's not uncommon for coils, especially fine ones, to fail open or intermittent. In the latter case, the coil could measure okay but open up when it warms up or is exposed to cold or hot temperatures.