Autopilot will not track the glide slope

Will the autopilot on the L1011 track the glide slope? I've done 15 flights (predominately using the INS). In all of them I've tried end the flight with an ILS/glide slope approach flown by the autopilot. The autopilot will the intercept the localizer (although there are some alarming altitude deviations when flying at 180-150 knots) but it will not fly the glide slope down to the runway (or close to it).

Maybe the L1011 isn't programmed to follow the glideslope?

Anyone else run into this issue?

The Manual, when describing the tutorial flight, instructs the pilot to disengage the autopilot at the glide slope interception point and fly it manually the rest of the way down to landing.

stevedel wrote: The Manual, when describing the tutorial flight, instructs the pilot to disengage the autopilot at the glide slope interception point and fly it manually the rest of the way down to landing.

Thats strange. My manual says
"As the localiser deviation pointer moves towards the central dot the aircraft will bank
right to intercept the localiser and begin descending to maintain the glideslope.
As you approach 300ft on the radar altimeter you will hear a series of beeps to warn
you that you are approaching the selected decision height. At this point disengage the
autothrottle and autopilot".

Have to say mine tracks the localiser and g/s fine, certainly down to the d/h warning where I take over. Must see next time if it will autoland if I leave it...