Hesitation.

The car runs good idle, it hesitates a little changing gears. I have ran the car up to 50 mph and the rpms are in range. I just cant step on the gas, I have to ease on it, but not to the fact I am holding up traffic. Ive notice by the top intake, behind it is a valve with a metal tube running to the exhaust. Is that pipe suppose to be well hot. I know it is suppose to be hot, but don't know how hot. Temp gauge is running normal. Engine light came on. Is there three catalytic converters on this model.