After changeing my oil, gearlube and fuel seperaters. While cruising rpms suddenly a engine will drop and spike and drop till i throttle back to idle and engine will either stall completly or stay at idle. If I sit and pump the balls every now and then while someone else drives no problem. The engines start no problem first start of the day but after that it is pulling teeth to get them started. Once started they work as stated above. Everything was working perfectly till I changed out the filters. I suspect I am getting air in the fuel line either thru the filter/speraters or before the filter. Either that or ethonal collapsed fuel lines. What do you think?