i would like to test the source voltage from the map sensor to the ignition control module and to the pcm ? i have a 2000 bonnieville ssei and think i may have a problem some where in that loop. also the vehical has had a seemimgly slite mis at idle and at light take off and seems to go away under heavy acceleration. at times i have retrieved at cyl. six misfire code .i have changed plugs and wires with iridium ac delco and wires from napa, the best they have, that injector, moved coil packs around as well as replaced one,and i have done compression checks on that cyl and fuel preasure test at the Schrader valve on the rail, and seen no problems. i have heard that the crank or cam? caused a slite vibration on these cars when new, and i read some info about egr gasses recirculating incorrectly? so if this problem sounds familer to anyone i would appreciate any info you may have. thanks.