while I have gotten half way decent at tuning a nitro engine there is one thing that confuses me when trying to follow a tuning flow chart or guide. One thing that never seems to be mentioned in them is what does it mean when your kit will idle fine but while its idleing it periodically revs a tad and then settles back down and just keeps doing that? Is that bad fuel? cuz I'm starting to think thats why I couldnt get my motors to run smoothly today. Anything else that causes that?