I have a 1999 1 ton GMC pickup with the 454 engine in it. When i crank it up in the morning it fires over fast with no problem but when i take off it actes like it has water or starving for fuel then you mash on the gas hard and it smoothes out, when i put on the cruise control it will have a slite jerking affect the or four times and smooth out till you hit the next hill up or down it doesnt matter. Then after the engine is warm i shut it off come back 30 minutes or so and its hard to start back up, but does crank. I had it in the shop for aoil change and had them change out the gas filter and the breather filter hoping this would maybe fix the problem, which it did not. Would appreciate any guideness that i could get on this.
Optional Information:
1999 GMC 3500 454
Already Tried:
changing oil over to rotella, changed fuel filter, air filters.