I have a 1994 4.3l S10 4x4 Blazer W VIN CPI 125k, Bought the truck used and ran into problems right off the bat, was told the intake was replaced about 30k prior, vehicle developed a massive transmission leak from the cooler lines 2 days later, anyway after driving vehicle had a rough idle but after a normal drive then letting sit it would run horrible, assumed it was bad intake gasket, also slight smoke and coolant smell. Drained Coolant from lower rad hose, Removed upper intake and found coolant in my Number 4 cylinder head, sitting on top of the valves, note system drained nothing in intake when removed. Took no chances, pulled both head and found cracks, installed new gaskets, reman heads, felpro permatorque gaskets, all torqued to spec, cleaned egr, installed screen gasket, new intake gaskets, new plugs, wires, cap, rotor, both new coolant sensors, vehicle runs great at idle, no signs of burning coolant, no smell, no coolant loss, timing at 0 btdc with est disconnected, vehicle has great power when cold, after 2-3 mins of driving, slowly gets worse, idle is rough but not unmanageable, slowly loses power until you can stand on throttle and not move. spider showed no signs of leaking, no coolant in oil/vice versa, any suggestions?