Running Rich At Time

[wade88]

So i recently swapped out my 4.0 from my 99 ranger. I bought an engine out of a 98 explorer. New engine was egr and mine wasnt so intake had to be swapped, a few other things as well such as distributor. Engine runs great id say 95% of the time. Sometimes it will take a spell and just run very rich, black smoke coming from exhaust and seems to be loaded up with fuel. Most of the time give it a few mins and it clears up and runs fine. MAF has been cleaned, o2 sensors are working fine and cats are new also. had to use the fuel rail from the truck but left the injectors that were in the explorer in it they are red the originals from truck are white. Getting a p1131 and p1152 code. on top of all that my mileage went from about 16 down to 11.2 last 2 tanks. Any ideas??

 

[adsm08]

Get the original injectors back would be a good start.

Different colors are for different flow rates.

 

[wade88]

Even though 95% of the time the enginene runs fine? I would think if the injectors were loading the engine that it would do it all the time temp gauge drops way down also when engine takes a fit