I've been using the Flysimware Cessna 402C for a while now and I love the model but I've recently run into some issues with the autopilot. I'm not sure if the issues are related to the updates Flysimware put out earlier this year or if it is user error on my part.

The first issue is whenever I activate the altitude hold mode the aircraft abruptly pitches down to about -1000 FPM before slowly leveling off and then pitches up to the proper vertical speed setting. What is the proper procedure of activating the altitude hold mode (and autopilot in general) and how do I stop this from happening?

The second issue (and this one I'm pretty sure is on me but I'm not sure what I'm overlooking to correct it) is occasionally on approach to an airport the aircraft will suddenly start to descend even though the altitude hold setting is still active and the approach mode is off. I'm assuming this is some how linked to the GPS but I don't know how to correct it.

I'd appreciate any tips!