I have a 89 460 efi 5 speed and it jerks real bad between 1600 and 2000 rpms. before 1600 and after 2000 it's fines. while regular driving it runs around 1500 and 1600 rpms. when you accelerate is when it jerks till it goes past 2000 rpms. sitting there at and idle it revs up great sounds good. i have changed everything you can think of. need to know if i am missing something.