quad driver a and b?

i have an 1993 olds 88 and it shows a code #26 and #56. they are showing in the current and history. i've found out that they control or monitor 8 different items between them. is this correct? also i have no idea of how to find out what is on each one,and how to test to find out what the problem is. the owner did state some sort of noise one day while driving that sounded sort of like the rumble strips on highway. also the car drove down the street and stalled. acted like it would not accelerate without stumbling. they drove back home at idle. i checked fuel pressure and it is fine. car will not cut off for me while it's idling but i have not driven it yet.

Here's a short article that might help.
http://www.troublecodes.net/articles/quaddriver.shtml

thanks mickey. it was kinda useful. i still need to know what items are connected to each module. have any idea asto where i can get that info because i couldnt find any on the net