What was the final fix??
 

I know this is an OLD post, but I'm hoping it will get a reply from you Tazman03....Just curious if you ever found the cure to your problem. I have an 3.8L 2003 Monte SS, and it's doing ALL of the exact same things as yours. The car just turned 90K on the odometer. I've removed the throttle body, cleaned it THOROUGHLY along with the MAF being cleaned and THEN replaced, new Idle Air Control sensor, new PCV valve/kit with o'rings, checked for vacuum leaks (visually only), catalytic converter is NOT glowing red at any point. Car seems to run fine most of the time, and then maybe once a day, it will have a rough start followed by hesitation, misfiring, and a lack of power. I can continue to drive it in that state and after about 30 miles, the car is back to fine for a few days. I see A LOT of people on here describing what sounds to be the same issue, BUT NOBODY ever says what they did to get it fixed! Maybe they're just getting rid of the car and giving up?? It sure would be nice to know how to fix it, IF you were able to do so. I do NOT think there is a transmission issue causing this. My tranny is fine, shifts great, no noise, etc. The hesitation and/or misfiring/popping is being caused by an electrical issue, but not sure what. A bad knock sensor perhaps? PLEASE let us know.

Hi Gary. As old as this post is you may not get a reply from tazman so I'll throw in my two cents. Do you have a check engine light? Based on the description you should have one. You can get codes checked for free at most of the big chain auto part stores. Considering the fairly low mileage on your car and what you've already done, I would be suspicious of the upstream O2 sensor.
Please keep us posted.

Thanks for the input Plumbob. This is a weird issue for sure. With my first attempt to solve this issue, I would get a check engine light right after the rough start up (code P0101 "I think" that's what it was). It said "low voltage to the MAF circuit input". I disconnected both battery cables, removed the throttle body, cleaned it AND the old MAF, cleaned the Idle Air Control sensor/valve, put on a new TB gasket, reassembled, cleared the codes, and fired it up. Problem didn't go away and got another check engine light and the same code. I took the car into a local GM dealer for an oil service and had them check it out on their machine. They came to the conclusion that they thought it was the MAF as well, but wanted $375 just for the new MAF and another $200 to screw it on and "calibrate" it. I decided to do it on my own, not feeling real confident that it was going to correct my problem. I didn't buy the Delphi part and I know everyone says you should, but I did buy a new Cardone MAF and not a refurbished one (which are out there). No more check engine lights after that, but it didn't solve my problems. It didn't even affect it. After a lot of research and trying to use common sense, last night I decided to replace the IAC sensor/valve, as well as the PCV valve and orings. MAP sensor looked intact and not leaking. I started it up, got it up to temp, drove it about 5 miles, bring the car up to about 65mph, and noticed on my return trip that the car felt like it misfired/hesitated again. My start ups are much smoother now (no coughing/sputtering.....yet), but I don't think the problem is fixed yet. This is my daughter's car and she lives in a part of town that I don't want her stranded in. Been driving the car the last couple of days and it seems like the issue occurs more often when the car is warm, bordering a bit warmer than normal. Driving the car all day yesterday...car was awesome....was on my last leg home to install the IAC and PCV kit.....running 70 mph at a constant speed, flat level ground, and the car started hesitating and misfiring/popping. Pulled off the highway, hoping it would continue to act up long enough for me to get the hood open and pull the MAF connection and/or IAC connection, but by the time I got the hood up, it was back to normal. DOHH!!!!! I checked the catalytic converter and it wasn't red, but I am noticing sort of a rotten egg smell to the exhaust. I'd be tempted to put on a new converter, but I'd like to be smart with my money and fix it correctly. Took the car to a local mechanic, and the car didn't act up, keeping them from being able to tell that anything was wrong with the car. Any input you have would be appreciated!!

Gary. This may not be what you want to hear, but I think it's the MAF and/or upstream O2 sensor. Just don't think it's the cat. with the mileage that low, and a clogged cat. usually throws a code. The rotten egg smell can be explained by fuel rich in hydrogen sulphide that isn't mixing/burning properly. Our cars just don't like those aftermarket MAF's, even new ones.The upstream O2 sensor reads the exhaust gas chemistry before the cat. and MAF reads air flow data. All this data is sent to the PCM which it interprets and commands the various components to adjust in order to achieve the ideal air/fuel mixture. If the data sent is false due to a bad MAF or upstream O2 sensor the data is skewed and everything gets messed up. High end scanners like Tech 2's can read the data in real time, freeze frame or take snap shot to this data for human interpretation of what is really happening, but that gets complicated. One other thing I would not rule out is the fuel pressure regulator. They were recalled by GM and can cause the upper intake manifold to literally explode if they fail.

Here's a video by Scanner Danner that I've found very helpful in understanding the process. I have a lot of respect for this guy. Hope it helps you.

Part one:
Part two:

Thanks for all of the info Bob. After reviewing many similar other links on these forums (and the internet in general), I decided yesterday to purchase the AC Delco factory MAF from Rock Auto. I knew our GM cars were partial to the factory MAF's, but I was trying to save some money and get the car fixed that day (nobody local had the factory MAF), so I chose the Cardone new version, wondering if it was going to work correctly. Luckily, O'Reilly's will return the MAF I purchased when I tell them that it doesn't work like the OEM MAF does. I'm waiting for the new MAF to show up now. I will report back in after its installation for follow up. If this fixes it, I will NEVER AGAIN buy any emission sensors from anyone other than AC Delco. Thanks again!

Great! Our cars are really particular about things like that,, as well as spark plugs, catalytic converters and some O2 sensors.
Please keep us posted.

To follow up, I replaced my MAF last night with the AC Delco OEM MAF and for now, it seems that all of my problems have gone away. Keeping my fingers crossed that this is the permanent fix for all of the hesitation, chugging, rough starts, and random surging idle. If it isn't fixed, I will definitely be back to this post! Thanks ALL!!!
Words of wisdom.....ALWAYS buy AC Delco sensors for the GM 3800 series engines!!!!!

Thanks for the follow up Gary.
Congratulations and I'll keep my fingers crossed for you also. :thumbsup: