Made some runs with a 150 shot last Sunday and it was missing on the top bout 1000 ft. so i shut off the N20. Fuel Pres. was bouncing a bit but never went under 52lb. It did this with a 100 shot too. It doesnt do it on all motor runs. Question is what to look for to solve the problem? Mods are in sign.
Any help would be great. Thanks in advance!

 

Are you using the right plugs, gapped correctly?

 

to much timing?

 

I say it is a lack of fuel.

 

Cold fusion is a wet kit right ? I would check fuel also.