I've got an 03 ram 2500 with the hemi and this truck has been great until recently. It's been in and out of the shop for this problem and it's still not right. Changed plugs and wires, put new 02 sensors in it, cleaned up the map and maf sensors and still it black smokes like it's a 78 mack truck. I'm getting terrible fuel mileage, around 6mpg, and its hesitating and stumbling all over itself. The only time it'll get up and go is when I really get into the throttle. Not sure where to go from here other than maybe a leaking injector or something but I dont want to just throw parts at it. Please help!