1998 Chevy Truck Runs rough after not driving for a week or

cattleman35 · Posted at Thu Nov 20, 2008 10:22 pm

Engine Performance problem
1998 Chevy Truck V8 Two Wheel Drive Manual 130000 miles

ok....I have a 1998 chevy 3500 crewcab dually 454 5 sp w 130000mi (woman owned prior to me) that has had a easy life. If i drive it every day it runs great...
but if it is not driven for a week or more after driving for 5 miles or so it goes to running rough with black smoke out the exhaust for 3-4 miles and goes back to running good. Does the same thing every time it is not driven for a week or more. A dealership I trust did a complete tune up which did not help I have also run several cans of b12 through it. Please help.....Thanks

bluelightnin6 · Posted at Thu Nov 20, 2008 10:42 pm

Black smoke usually means that the system is running too rich, in other words too much fuel. I am not sure what you had changed in the tune up but change your fuel filter if it wasn't changed. I would also suggest changing your 02 sensors.