Why would my truck be lacking in power and running rich

Ronnie Owen you are not giving us a whole lot to work with here. It would be nice if you let us know the year and model of your truck as well as the engine size. Best thing to do at this point would be to scan the OBD and see if it brings up any codes. This could be anything from your O2 sensor to your fuel pump to your injector right up to your crankshaft position sensor etc.