Please Help Something Went Wrong

I Had A Head Gasket Job Done To My 1997 Chev. Tahoe Truck..... For About 3 Weeks The Truck Had Been Running Fine.... This Weekend I Went To The Bay .... Have To Pass Some Steep Hills .... All Was Fine.... Until I Arrived Back Home..... Truck Not Working Fine Anymore...... On A Stop Truck Seems To Want To Stop On Me......i Put Gas And It Yanks On Me ......... Check Engine Light Has Not Came On..... What Might My Problem.......we Also Put New Dist. Cap And Roter...when Job Was Finished....

This Is The Family Vacation Truck And Kids Are Almost Out And Have Plans To Go Visit Family In Mexico (3 Day Trip to get there)
Help..............help..............help.......... ....help...............help......help