using cruise control going about 70mph, when I go over rough bridge joints, the cruise control backs off the throttle a lot. Sometimes, it gets stuck in a weird on-off loop and i have to turn the cruise control off then back on and it's fine. if I give it throttle while in the loop it accelerates fine, but I think it returns to the stumble like condition. I say "I think it returns" is because I only experimented with accelerating while it's doing it only once, and just enough throttle to get it off the deceleration, and as soon as i let off the pedal, it went back to doing it so i tapped the brake pedal, set cruise again and it was fine. But it does do it on the harder bumps, the ones that make the suspension vibrate. if it is smooth enough for the tires and shocks to handle, it's fine

 

You're most likely experiencing some wheel hop in the rear end on larger bumps which is causing the wheel speed sensors to have messed up readings and de activating/messing up the cruise control.

 

I kind of came to that conclusion myself, and figured I would ask here if anyone else is experiencing the same effects

 

I agree with xsfun.. Might be time for new shocks or less air in the tires