Does anyone know where I can get an engine computer electrical diagram for a 2005 Bonneville GXP?

Is that the 3.8 or 4.6 liter engine?

It has the 4.6 northstar engine

My 1994 bonneville ssei got problem
service engine soon light came on dash - took to mechanic he said computer is bad as it is also missing fire to number five cylinder. he proposed replacing computer. I replaced the computer bought from autozone and now I have swapped two computers with them but the problme is worse as flase info lights on dash. what I am doing wrong when
putting in the computer. thanks for any help

Try going to the library and if you are not a member, join and ask if they subscribe to Mitchels OnDemand. If they do you can find most anything you want to know. This is the same site used by mechanics all over, even dealerships. I was looking for a wiring schematic for the charging system for my 97 Bonneville and all I could find was the same everywhere and did not show the wiring I had. I went to the library and found it at Mitchels OnDemand website. You could subscribe, but the cost is several hundred dollars a year. Why pay that when the library is free.

Hope this helps.