97 Bonneville, pulsing

I have a 97 bonneville that I got for basically nothing, thought heads where blown, incorrect, was upper intake around egr melted and puttign water into cylinders, I read a former post abotu the pulsing while driving but fine while on level plane, only proble with your answer is, I changed the egr when I changed the upper intake, granted its not a bad pulse but you can still feel it, I changed the fuel regulator, and twice ive changed the plugs, and wires once, any other ideas as to what may cause it? I was told maybe a speed sensor in teh tranny? But that seems a bit much, any help is appreciated. Thanks!