My truck started to overheat(never touched red line)and run rich at the same time. It got hot due to lack of coolant so I add some and all problems went away. 2 weeks later it ran rich again and continued for about a month and randomly went away. Now it's starting to run rich again and it running a little rough. The cel has never came on. When I first start it up I see black smoke. As the truck warms up it doesn't run as rich. I get horrible gas milage. Any ideas?

 

if its running rich at normal operating temp, it could be a bad front o2 sensor or leaking injector.

if its running rich when cold, i'd guess a leaking injector.

pull the plugs and see if one looks a lot worse than all the others.


edit - if it keeps losing coolant you need to fix that or else fill it up every week or day. look for leaks, especially around the water pump pulley.

 

New info. I found out my cel doesnt work and is is throwing the code bank 1 running rich. The guys at advance told me it the o2 sensor but it cant be because when i start it up and turn around I see a cloud of black smoke. The gas smells like oil just to mention. Thanks for the info dhvaughn and I do believe it is a leaking injector.

 

if you have a junkyard around, you might pickup one or more used ones for little to nothing. use new o-rings for the install, and lube with vaseline or something. o-rings can be had at your local parts store.