i checked the code on my 95 k1500 and its sayin coolant temp sensor open. i changed the sensor on the side of hte head. and its running rich what could be causing this?

 

wrong sensor to start with, that sensor is for the dash guage, the one that you need to replace is in the middle near the thermostat housing, one Black wire and one yellow wire, it is running rich to attempt to cool the engine down. theory 101: in todays engines we run an optimal AFR (air to fuel ratio) of 14:1, when in fact optomial burn ratio is much less fuel. but at much leaner ratio, the cylinder temp will excede design limmits, hence frying the entire motor. so we preform a manuver called fuel dumping. this puts fuel WE know will not be used in the combustion process. but it will draw the excess heat to the unburnt fuel and carry it out of the motor via the exaust. then the catalitic converter burns the unburnt fuel. so now back to your problem. the ECM thinks it is REAL HOT and atempting to pull heat out of the motor, Is that clear as mudd?