Cadillac Repair: 1998 cadillac deville, exhaust gas recirculation, cadiilac

Question
I have a 1998 cadiilac deville with a northstar engine. Fot the last couple of days my car has been jerking a little when i put it in reverse and when i press the gas to go it stutter a little like its about to run out of gas. i changed the spark plugs but not the wires yet. when i did the off and warmer thing to get codes it read rcm p0401 current, pcm p0550 history, ipc b1552 history, acm 1983 history, no sdm codes, no tsc codes, no pzm codes, no irc codes, no rfa codes, then it reads pcm? and then the codes just stop and stays on pcm?  please tell me what to do.  

Answer
You have a fault in the EXHAUST GAS RECIRCULATION (EGR) system. You need to perform some test procedures via pictures.

If you are mechanicaly inclined or know of someone who is, You will need simple electrical schematics, Test procedures and picture locations of the components within the system that is causing you problems of which can't be done on this website which only allows one picture. I do not have a website so you will have to e-mail: onlineautohelp@msn.com in order to obtain the information.