looses power after it is warmed up. 2.9 l. acks like no gas.

sounds like if its over heating,have u checked your head gasket.my brother's 2.9 had the same symptoms and thats what it was.

Not over heating barely gets warm. Will gain power back if I down shift.

have you changed the thermostat lately???? ive heard horror stories about ppl that have changed the thermostat and put the wrong temperature thermostat in the truck.. one that the temperature was too low. and the truck would not run right.... i would say put a higher temperature thermostat in the truck and see if that might be your problem.

Have not changed but wad going too.

have u changed your fuel filter lately.

Yes I have both of them and the high pressure pump. Pick up pump runs great. Does use a little oil. Why would the truck leack. Antifreeze out the back of the block left side (drivers)?

check if the coolant isint coming from the head,or your block might be cracked.have you had it for long,maybe the previous owner ran it low in coolant and over heated it.sonds like the head gasket to me.cant run it with bad head gastek you'l warp the head.