I just purchased a 2008 Silverado it has the 4.8 I took my first long trip in it and when I was running with the Cruise on and went up any kind of hill the engine would race and the tranny would shift to passing gear. should I have the dealer look at this? Thanks

 

na, thats normal. when Im traveling on fairly hilly interstates I speed up before I start to hit the hill then slightly reduce my speed on the way up till im near the top then I let all the way off and let it resume to whatever the cruise was set on.

My truck does it a lot less since I got a tune and took my bigger tires off.

Its no big deal but I do what I do to save a little on gas.

 

An intake or programmer would help you. Your truck has to work harder to move itself up hills with the smaller motor.