1992 olds 88 want start

Hi, I have a 1992 olds 88 It started to run bad would only go about 20 miles a hour then when cut it off would not crank back. Replaced fuel pump, ecm, crank sensor, computer, coils wires plugs, tries to cranck but want. It does have pulse at injectors, does have fire at plugs not sure how much. But does fire. Turns good has good compression on cylinders. Any ideas what to do. Thanks Gary