There are issues that aren't user fixable or that I would even recommend a user fix. If you aren't sure how to do something, play it safe and send it back to the guys who built it. I consider myself to be competant but the guys at the factory and traveling techs know more about this stuff than I do.
At the store I used to work at, we charged 45$ just to look at an electronic marker. Any parts that were needed were called before they were put on.
The solenoid is something thats hit and miss. If its an old SFT, then yea, it may actually be the noid. Most of these guns have dual regulators and a series of other items than can affect pressure and velocity. The solenoid should be viewed as a last ditch attempt. I very seldom have had to replace an Intimidator or Ego solenoid.