No pun intended on the subject. Ahem...I seem to be having a problem getting to cruise altitude and/or staying at FL550. I like to start in a cold and dark cockpit, with avionics set on already. I start her up, get her in the air and the climb usually goes without a hitch with my VS and ALT AQ buttons pressed and HDG TRK. However in one flight from KLGA to EGLL I started losing speed at appx. FL 240. Maybe about a knot a second. So I checked over my autopilot and nothing looked out of the ordinary. So I disengaged autopilot and pitched to about +500 fpm and gained some speed, but after a few seconds started to lose it again. I hit the relight and gained some speed but still lost it. In another instance I made it to FL550 without any problems and continued to cruise. However I could only acheive Mach 1.4 with a 69 knot tailwind and relight on. And soon enough I began to lose speed. My fuel load seems to be ok, but in both instances I have to pitch up to maintain my altitude and before I know it I am pitched up to 60 degrees and losing altitude with afterburner and tailwind. Has anyone else had this problem. It is frustrating to get all set up, INS wayppoints loaded and at altitude when this problem occurs. Any help would be appreciated as I have grounded the fleet until I can fix this issue, among others like the nav1, nav2, adf radios going out on me. Thanks in advace.Ryan LandisUSAF Air Force Special Operations CommandMC-130P "Combat Shadow" Crew Chief