What is the response from dead stop? Is it near flooding on the low? I know you can very easily have the low end too rich and the high end too lean and it will still idle fine. You're basically masking the lean high end due to having it very rich on the low end. What you need to do to fix this is start by leaning out the low...usually quite a bit...dont worry about the idle yet..get the low to where its not bogging off the line and you have good response...then richen up your high end...finally get your idle in check and it should be good to go. You can check out
http://www.rctech.net/forum/nitro-of...ing-bible.html
They explain this better than i can. Good luck.