GMC TYPHOON ENGINE SYMPTOM

Ok So Here We Go. I Bought This Truck 3 Years Ago And I Havent Started Working On It Until Recently. This Truck Suffers From A Series Of...

Typhoon Starts Fine Idles High Then When Idles Down Truck Starts Smoking Bad And Stumble Bad On Acceleration And Then Dies. Put In New Fuel...

Turn Ignition Switch On A Braker Shuts Down Start Circuit, Turn Switch Off It Resets Until Turn Back On.

My Truck Has A Fresh Tune Up, Good Spark, Proper Timing, Fuel Pressure At 36psi, With The Vacuum Hose Applied, And Ran Good Yesterday....

Engine Has Been Running Good, No Problems. Went For A Drive And Engine Started Running Rough At 2000 Rpm, Anything Above 2000 Rpm Runs...