Hi Everyone!

Just a quick question.  I'm flying the 757-200/300 and I am really having an issue with the rate of climb.  After 8000ft or so, it slows down to a crawl ... after nearly 250nm of climb its only at 23000 - when i should be at FL370 (according to my FP).  When i attempt to manually force climb to faster rate, the speed starts lowering.  Is there a bug that i need to delete? Also,the "clb' switch - should that be pressed?  Is it modelled?  What does it really do?  Thx > Bondi