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.

First off, its very difficult to read what you are trying to say without proper punctuation and grammar.

With a 3800 #6 misfire, it can sometimes be related to the EGR pipe being cracked because the EGR is closest to #6 or the EGR is not closing all the way.

According to my 97 Bonneville schematics, the MAP sensor is fed 3V from the PCM and does not connect to the ICM. They are on their own circuits. If you are talking about the MAF sensor, it gets 12V from ignition power(not to be confused with ICM)

Thanks and sorry. I am reffering to the map and not maf. And i was expecting to find a 5v ref there not a 3v. So if that is the case i may not have a problem there. I found a 3.7 or something and dicontinued. Also i could not find any exaust leaks though it does sound like there is a small leak somewhere. I have replaced the front pipe. Anyways let me know what you think.

You probably won't "find" a leak. You have to remove that little EGR pipe and visually inspect it for holes or cracks.

Ill check it out and let you know thanks.

I would also be on the lookout for vacuum leaks elsewhere in the engine bay as well.

I think i have eliminated vacume leaks and while i have not taken the egr tube off they both look great from the outside and a few mounths ago i ran something like a brush threw it to make sure it was clean. I also checked the egr with my fluke meter to makesure it was in fact operating correctly.

at this point I have taken the throttle body off , cleaned it and installed a new gasket . While I was in there I took the EGR off and both EGR tubes going in both directions from the rear manifold and to the intake. They have no holes or cracks in them. Also I seemed to be leaking oil from the valve covers so I changed them. At that time I rechecked all vacuum lines and all sensors for leaks and poor conections. I still have a slitely ruff ideal, and it seems to still be there at hard acceleration now. Also I still hear the exaust and cant find a leak. im thinking mabey the rear manifold must have a small leak.