When I am driving up long hill on the highway in cruise or not me engine will cut out for just a second- it sounds like a automatic starting to down shift. plugs/wires/cap/rotor/coil all new within the last 3 years. Everything is clean and good running order and this only happens on long -kind of steep hill - ozark mountain-ish kind of hills. Any thoughts? I do have a slight crack in a weld on my exhaust manifold but after that its all new.