Cadillac Repair: 1995 eldorado running rough, cold air intake, flow mufflers

Question
QUESTION: hey i have a 95 eldo vin y 4.6L north* and just recently it has begun to run rough at idle and through acceleration. it runs fine at WOT and has all the power it should but when accelerating like a sain person it is weak and stumbly (you can feel it and the exhaust note isnt normal). the whole ignition system is new (accel performance coils 2 weeks ago, wires and plugs less than a year). i also put a cold air intake on it 2 weeks ago and it was running great. there are no dash lights and the only codes in the computer are for the suspension which have been there for a long time so are not related. i am an aircraft mechanic so i know my way around a toolbox so i HATE taking the car in for someone else to fix and wasting money. any suggestions will be much appreciated. i also tryed to "re-flash" the computer due to the new parts by holding the engine at 2000rpm for 3 min. did i do this right or is there a better thing to try? could it be a plugged cat? i do have high flow mufflers but the exhaust is otherwise stock and the car has 86000 miles on it. thanks
James

ANSWER: There is NO procedure for reflashing the computer. I would run a back pressure test on the exhaust system to see if you have a restriction.

If you remove the air intake hoses and expose the throttle plate area you will see that there is a blackish residue buildup within the throttle body and on both side of the throttle plate. You need to clean all areas of the throttle body  with an aersol cleaning agent.

---------- FOLLOW-UP ----------

QUESTION: I did as you said with the throttle body and it was quite gunked up so I cleaned it as well as I could. Then after I got it started it ran better but still was not right so I disconnected the battery for awhile for the pcm memory to be reset (suggested by a fellow gearhead), following reconnection of the battery I went on a 20 mile trip on the freeway and at highway speeds the car is great, at WOT its very powerfull but when ideling in park it wants to stall and rev's itself to stay running. also it sounds as if it is running very rich (exhaust is very deep and actually resonates through the car which it normally does not do) and lacks power on normal acceleration but the stumbling problem seems to be gone. my question is could my plugs and/or my O2 sensor be fouled? or do you have a better idea? your last suggestion seemed to fix part of the problem but reveal another. The O2 sensor is original and the plugs are bosch platinum +2 (less than a year old). both are inexpensive and easy to replace so should I try this (I changed the O2 sensor on my 93 cutlass even though the check engine light was not an and it made a very big difference in mileage and smooth idle), or could there be a bigger issue here. any help would be great because this is very frustrating and my car is sucking down gas like a raging alcoholic which is no fun. Still no dash lights and no codes in the computer, Oh and if this helps all this revieled its ugly face about 1/4 tank after i filled up with gas, I always fill up at the same shell with their premium fuel which is supposed to have injector cleaner in it so i doubt my injectors are fouled. Could this just be a very soiled tank of gas? thankyou for all your help and it is very appreciated.
James

Answer
By disconnecting the battery you erased the computers memory of how the idle speed should run. You have to perform a RE-LEARN procedure in order to get the computer to re-memorize the correct idle speed.

You can obtain picture directives by e-mailing: onlineautohelp@msn.com as PICTURES are not allowed on this particular website.