Hi fuzzy11

I suggest you do the 757 FMC Tutorial (by aussie) HERE so you can get a feel for what is required when using the FMC. Going by this and you other post, you might have missed something.

So, I thought I'd try a climb 2.   I set the usual EPR/LNAV/VNAV.  It only climbed at 1500 FPM and around 160 knots.
I mostly use a Cost Index of between 20 and 100. The higher the number the faster the flight and the more fuel it will use. I never touch those buttons as the FMC controls the engines. I'm not good at Flex takeoffs, so most of my flights are done using TO/GA, CLB and, CRZ always controlled by the FMC and never by me.

Practice...practice...Practice...practice...
Yep! That is certainly how you learn. ;)

Mark