I have tried every combination of ZFW, reduced N1 climb power, reduced target speed during climb and reduced OAT.Acceleration from V2+10 to 250 is normal - 800 to 2000 v/s, depending on the parameters above. When the speed reaches 250, the pitch increases and the climb rate rockets to 3000

There is no such thing as "normal" climb rate when it comes to VNAV. Everything is relative to weight, power, weather and temperature and maybe a few other things. (quote from Randy Smith).Volumes have been written on the subject - I suggest you use search button.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2

Nameless,What is happening is the aircraft is using the proper climb rate to keep the speed at what you have told it to be. The goal is to get as high as you can as fast as you can and keep it there until as late as possible. The aircraft is most efficient at altitude. That being said you can choose which type of profile you want. An example is after the T/D if you have SPD selected it is not going to care about the path for the way down the only thing it cares about is the speed that you have told it to do. It is going to change the pitch to do that. If you have it set for PATH then it is going to follow the computed path down and not care about the speed. In the path scenario you must watch your speed and make sure you are not going too fast or slow. It is all in the manuals and tutorials. By the way forum rules state to use your real name.

Hi ??????????According to my real-life UNITED F/O 737 pilot friend, it is not unusual for the jetliner A/P to command a climb of 3000-4000 fpm sometimes.Kerke :-waveKMIA