Lumina 3800 V6 issues

I have a 95 lumina 3800. Lately it stutters while driving like a missfire...gotten worse lately.. THEN today start it up and it idles like
new for 1 min ...then idles up and down like an idiot from 200rpm to 1300 for about 10 seconds and idles out fine then starts back up in the idles surges.. What would cause this.. I replaced all the plugs, fuel filter, air filter oil etc as it was required. I tried the paper clip scan but this stupid thing has the weird OBD I scan plug that can't be doen with typical OBD I gm scanners ($19 at parts store) so I can't scan it to see what it's problem is. Thanx for your time
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You really should try and do a full scan, too many things can cause this, vacuum leaks, carboned up egr, bad maf, low fuel pressure.

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I am scanning it tomorrow.. I have a buddy who has a snap on scanner.. it reads this type off plug..

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Chevrolet, I agree with Shep: have this puppy scanned. The 1994/95 3800 Series 1 engines are a bit weird in that they have OBD1 connectors but generate OBD2 codes AND don't have the "B" contact populated so the old "watch the blinking Check Engine Light" scan will NOT work. My 1994 Regal is this way too. These cars are sometimes referred to as "OBD 1.5" cars.
If I have to take an educated guess as to your problem, I'd rank in this order (AFTER checking the items Shep mentioned): Throttle Position Sensor, then Mass Airflow Sensor.
Regards, Bill Bowen Sacramento, CA

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well.. had it scanned... O2 sensor. Seems to have made it better but number 4 cyl is not pulling like the rest adn it has a slight rough idle to it.. I changed the coil pack and plug/wire but thinking she has seen better days 226k on it. Does run not bad though. just at idle in park it seems to stutter a bit... fine under load. If anyone has any advice on what would cause minor miss or vibration only at idle while in park.. but fine in drive etc.. I am all ears.

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Chevrolet wrote:

Is that all you are worried about? That it idles slightly rough with no load? Personally, I wouldn't worry too much about that. Many of the vehicles that I drive in and out of my bay all day long do the exact same thing. Smooth right out as soon as you put a load on.
Ian
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