Originally Posted by 88pathoffroad

Try cleaning your O2 sensor. Remove it from the driver's side exhaust pipe, let it hang down and heat the tip with a propane torch(NOT MAPP gas or oxy-acetylene), until red-hot and the flame from the torch blows red behind the sensor. Let it cool a bit, then torch it again from a different angle until all carbon/etc deposits are cooked off. This really works and can be used to eliminate buying a new $135 oxygen sensor. Other than that, your EGR valve may need cleaning.