Quote Originally Posted by speedminded View Post
Check the oil? Is it clean or milky or smell like coolant? My guess clogged cats...
That very well could be the problem also, but normally the CEL would come on. Check the the consistency of the oil and jack up the car on both sides if you can and check the catalytic converter. Pull out a spark plug and poor a small amount of oil in there and then put the plug back in and fire it up. Check under the car to see where the problem might be.