got a 1999 Dodge Ram 1500 5.2 Liter just put a new engine in it and cant seem to get it running correctly, its running extremely rich and just falls flat on its face if you put a load on it, tried cleaning the grounds, switched out all sensors on the throttle body, cleaned the throttle body, check the cat and looked good, checked the o2 sensors and seem to be functioning the way they were supposed to, checked for intake leaks and was unable to find any leaks so its got me scratchin my head as to what it could be

 

Is the coolant temp sensor broken? Not plugged in? Should be near the thermostat housing. (yeah, hard to see down there.)

 

"
New engine" did you have the distributor out? If so need to have the fuel sync set.