I have a 1997 GMC Sierra with a 5.7L V8. I am experiencin g a shudder when coming out of power when climbing a hill or coming out of a poweredsituation. It happens like clockwork when coming over the top of a hill. Once accelleration is applied it stops. 2 mechanics have referred to it as an issue with the torque-converter lockup. I have read a few comments online about a misfire causing this when at low rpm's, which is when this seems to happen. Any help would be greatly appreciated.