feathering throttle?
 

I have a 06 250 Powerstroke. I'm the 2nd owner and it has been built by the previous owner. Here is what I know. EGR delete, ARP studs, banks techni cooler, AFE cold air intake, 4 or 5" exhaust, 37 inch tire, SCT livewire. Here is my question, the truck has aftermarket injectors, my mechanic says they have been bumped to 20????, he says it has 20 nozzles I'm not sure what that means or what size that translates to neither did innovative diesel..with that said innovative diesel gave me 3 custom tunes when I got the Livewire, it runs good but sometimes it sounds as if I'm feathering the throttle when I'm getting on it before building power again to accelerate, and at times there is quite a bit of turbo lag as I try to accelerate to pass someone...I hope y'all have enough info to try to get me some suggestions.