I'm having a problem getting the ILS to track the GS  successfully.  It tracks the localizer okay but, when the GS locks on, it is sluggish and erratic at best. It appear to track, then lose it followed by excessive rates of climb or descent.  All indications [ Lights] show a lock on of the GS.
I believe I'm familiar with the procedures to use with ILS.     I love this A/C even with this Glitch.  Anyone got any ideas what is wrong, or is it just finger trouble.  

Seejay:

Try this: Go to the altitude at which you expect to intercept the glideslope, set the AP to Altitude Hold, then engage the G/S Auto position on the AP. ILS Lock will remain green and G/S lock will be yellow until intercept, at which time the Altitude Hold will desconnect and the G/S light turn green. The airplane will follow the slope correctly. For some reason, it pitches up slightly just before starting the descent.  

I've noticed that if you engage the G/S Auto position and continue to make manual changes in altitude, the airplane behaves as you described.