astro van/ service engine soon

checked code #42, replaced cat converter,oxygen sensor, temperature sensor,in module, plugs cap, rotor, coil,thermostat. still getting service engine light. van starts and drives good while cold. after about 10 miles the engine boggs down no power,seems to be starving for air. excess heat on right side of engine. I do not know what to check next. I'm spending lots of money. any help will be appericated. also you have a good web site. Thanks in advance. :confused: :confused: