I have a 2001 Ford f-150 4x4 Supercrew Lariat with a 5.4 l engine and 165k miles. The intake manifold cracked at the crossover tube in March, which I replaced. On Memorial Day, it blew a short hose on a riser coming out of the aluminum crossover tube, and now it seems to be building excessive pressure on the drivers side. In addition, I started getting a misfire in the number 5 cylinder, which is right next to the crossover tube. The coil pack was damp from anti freeze, so I suspected the crossover warped and broke the seal contact, so, since the manifold was still under warranty, replaced it again. Now I am getting a misfire on no. 8 cylinder, but only when the engine is at operating temperature. There is a rear coolant crossover next to the no. 8 intake port. Engine temperatures using the OTC scanner remain at a constant 208 degrees F, but I am still getting a coolant smell and the antifreeze, which I have drained (and saved) looks like a muddy creek! Got any ideas?