GMC 1995 4.3L VIN "Z" TBI Rough Idle & Exhaust Smell

The engine in my truck is a 4.3L VIN "Z" TBI and I recently had the intake manifold resealed by a GM dealer. Ever since then the engine has idled exceptionally rough and from the smell of the exhaust it is also running rich.

The dealer claims they can't do anything else with it and tell me that "all 4.3L idle rough", but this is something beyond the ordinary and wasn't doing it before I took it in for the manifold repair.

I have also had a tune-up with new spark plugs, throttle body decarb and fuel injection cleaning. I have not replaced the cap, rotor, or spark plug wires.

I need some help with this because I have a mountain vacation planned in one week.

Help & Thanks,
Scott