I just purchased an 03 rcsb 4x4 with a 4.8. It will take off from a dead stop fine, shifts through all the gears fine. When I get above 60mph though it begins to jerk as I accelerate. My rpms never jump so I don't think it is slipping. Any ideas what this could be?

 

A transmission doesent jerk..sounds like you have a problem in the motor...have you checked sparkplugs and cables

 

How old are your plugs, wires and coil packs?

 

Yea your right about it not being the tranny, not sure what I was thinking. Plugs and wires I assume are original, I just got the truck last week. I'll start with that and see if it fixes my problem. Thanks.

 

no check engine light? misfire code?

 

Another thing to check is the break switch

 

No check engine light, no codes.

 

I'm not 100% sure I know what your talking about. Is it somewhere on the brake pedel?