I've been having a similar issue recently with my 05 GX, but the problem is that the ride is too high. My commute is less than 2 miles round trip every day, but when the suspension is on the fritz the ride becomes so bad that I wouldn't be surprised if the rear axle detaches at some point. Thank goodness I haven't had any passengers recently as I fear they would have been catapulted into the ceiling.
Moreover, the height control indicator intermittently flashes "off" and it doesn't seem to always coincide with when the car is riding rough. Sometimes the problem seems to correct itself. For example, the ride was terrible leaving the parking garage this afternoon, but when I got out at a mailbox less than a 1/2 mile away, everything looked normal. I got back in and the rest of the ride home was fine.
There are a number of other GXs in my parking garage at work and I've parked alongside for comparison, the gap (between the top of my Michelin(s) and the upper part of the wheel well) is significantly higher than the other GXs I've compared it to. Does this sound like the same solenoid issue?