i have a new Adam E3 (about a month) and i notice that when i play long notes up the scale and hold down the fourth valve for a long time, it is sometimes sluggish coming up. But if i push it down again quickly, it comes right up. I used to have the same problem with the second valve on my Besson and even on the second valve when i had a trumpet. I always thought that maybe i was not pushing valves down straight or something.
I do clean my valves often and even after cleaning and oiling, this has happened.
Has anyone else come across this. I have had a valve stick in a concert which is not a good thing (but that was the Besson).