I have a 2002 f150 5.4 4x4. It has 270k miles on it. When I turn on the AC in the truck, it feels like I lost 80 horsepower and it just drives terrible. The transmission feels like it's shifting weird and hard and I really have to floor the gas for it to get going but when I turn the AC off the truck drives perfect, full power and the the transmission shifts like normal. btw the ac is entirely new, I'm not just talking ac compressor but the evap, condenser, accumulator and lines are all new. it wqs also doing this before I replace everything. the engine light isn't coming on so I just really don't know what's wrong.