vector226

Also, make sure you hit the buttons on the A/P to activate Heading and Altitude, or it won't recognize them.

First of all, before you turn your A/P on, make sure your correct altitude is set in A/P. Then set your Nav/GPS switch to GPS. This will tell the A/P to follow the GPS route. If the switch is in NAV it's going to follow whatever heading is currently set. This would make the plane turn hard to get to that heading. If you haven't set your altitude, It's going to dive to zero altitude. I hope this helps.