I have an echo pb 755H blower that when run at full throttle it will bog as if its loosing spark. It only does it after about 10 to 15 mins of use, then will continue every 5 to 10 mins give or take. Issue started the end of last season, thought I had it fixed with a new coil and boot, but its still there. Background info: -new intake gaskets -new coil and boot (issue was there before new coil) -newer plug -exhaust clean -was bought brand new in either 07 or 08 (still seems like it runs strong even with the issue) tired running with kill switch disconnected, still ran the same. Anyone have any ideas?