Autopilot issue

When my aircraft reaches it's assigned altitude on autopilot, I always hace a nose-up attitude, never horizontal. I checked to make sure my flaps were up; everything is calibrated. It doesn't matter which aircraft I use, I always get the 'nose-up' attitude. Any thoughts on this! Thanx!

Really depends what you consider 'nose-up'. If its 5 or so degrees up thats normal, but if its something like 25 degrees, your not maintaining the required speed at that altitude, in big airliners, you can not climb straight to 38,000ft at 3000fpm at MTOW. So depends what exactly you consider nose up!