Ok maybe my first post was way too complicated and too many questions involved so lets break it down.. !st of all on a 1993 Bonneville sse, my shop manual talks like the ecm/pcm is located on the passenger side under the dash inside the car.. Do I have to take the glovebox out to see it or locate or access it? Is this a common thing to go bad and are there any test to tell if it is bad other than rapping on it when it is running and checking codes to see if bad ecm code is present? My guess is that it is common for it to be bad without showing the talked about error code...

The manual always talks about checking continuity between the ecm and the various sensors.. so I am thinking how do I do that.. guess have to somehow fix a wire with clips or something in order to fasten one end to ecm connection want to test and one lead of the multimeter then touch the other end to appropriate place on the sensor?

Thanks in advance

Remove the passenger side hushpanel......above your passenger'* feet. You'll see the silver box. That'* the PCM. The Eprom is under a small cover on the box.

To check sensors, you'll need a factor wiring diagram, or at the very least, Chilton'* #28200 (about 15 bucks). Use an a wire with an alligator clip on each end. Ground the sensor wire you want to check, then check for ground at the PCM plug. Do this with the battery disconnected.

What symptoms are you having?

Thank you so much it sounds so simple when you put it like that .. Thanks so much for the info..
As for the problem I am having you responded prior to my other post where you said it would take some time.. Basically, my engine stumbles, with complete loss of power everytime I try to accelerate or start to pull a hill.. It is posted in detail under engine stumbling please help.. so far you are the only one to respond to it... any tips? Remember that was the one where while testing fuel injectors I had an engine fire and now I have to repair wiring before can do anything. However, also still in the back of my mind as to what the heck could cause this much havic with my engine.. I am thinking ecm and have read some other post that sounded similiar...

Sorry. I answer a good hundred posts a day. Hard to remember who has what nightmare.

Your engine fire still scares me. You may have ALOT of damage, and I still think your best option is to replace the entire engine wiring harness. We can't go any further until you get any and all damaged wires replaced/repaired.

thank you so much! I am new here and I think what you have is a great thing and it is awesome that you spend so much time helping people. I am planning to replace the entire engine area wiring harness... My fear is that anyother old or high mileage donor car would or could also have less than ideal wiring. Maybe I should just focus on getting the connectors that way and try to replace wiring with new? I have pulled those pins out of connectors a few times now that I think about it and am sure I could find a way to crimp the pins to wire although may not be very professionial job, can you buy pins for such an undertaking or would you not recommend this? I guess now I need to figure out what year models would be the same as mine, looks like it would definitely have to be a supercharged version? I know on most cars when I have looked up possibility of buying a wiring harness seems they usually have 2 to 3 major loops or separate systems. Does anyone know how many this car would have? I guess once I get to unravelling it all and tracing it I will be able to tell where it goes and what all it connects to. Seems like quite and undertaking - I invision having my dashboard area and firewall totally disassembled???

I was thinking a clogged catalytic convertor.

I kind of doubt it would be an ECM problem, unless you're getting Check Engine lights, etc. If the ECM is functioning normally, it'* not going to run out of breath or be unable to keep up with higher engine speeds, in other words, although a blocked exhaust can and will cause the engine to stumble and stagger when you gun it to go uphill or hit high speed on the expressway.

thanks for the response! I kept thinking the same thing, I had ruled it out since I had a muffler shop check this.. Perhaps I should get a second opinon or just cut the dang thing off to be sure...

Disconnect your battery for 30 minutes. Reconnect it and drive the car if possible (or at least start and idle for awhile). Then turn it off and use the procedure in Techinfo to pull codes. I'd like to see a fresh set.