6.5 Smoking and running rough

[DaveEh]

Howdy

I have a friend who has a 1996 6.5 GMC Van and he came in from a trip and then started out about 3 ours later and when he started the veh it came out running rough and spewing blue/black smoke. Now runs very rough. Has about100,000 miles on it. Any suggestions. Thanks

[charliepeterson]

Being a '96 and OBD II if the engine is running that badly it may have logged an engine code? If the Injectors are original, after a three hour trip and 100K, one or two may be failing?

[DA BIG ONE]

I had about the same problem, turned out to be the turbo boost circuit.