lipo vs life probably won't see any change... your talking 7.2V vs 6.6V and both are within the recommended ranges.
there are other threads about OTHERengines that have had issues with the higher voltages of these batteries... switched to a 4 cell 4.8V nicad and the issues went away.
Personally I'm flying the 4.8V nicad.
ORIGINAL: ozzydude
Just got done flying and the day started out kinda bad cause the motor starting missing real bad in the Meridian and couldn't figure out what was going on. I checked for air leaks and all was good. I replaced the spark plug and still the same thing. Then i looked at my voltage meter when at WOT and it was going from 6.5 down to 4.0 and bouncing around inbetween. I'm using a new 1100 liFe pack for the ignition that i charged this morning so i put it back on the charger and it only took 190mah to top it off. I put it back in the plane and problem was gone. I flew it for 5 more tanks without any problems and motor ran great. So not too sure what to think of it. Maybe i'll just get a lipo instead for ignition. Anyone else came across this problem?