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need help with an 06 Grand Prix

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Old 08-16-2010, 11:12 PM
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thats actually the first thing I considered since these things are notorious for theyre popcorn fart trannies. The guys at the dlr said it was ok, but how does one check the tranny? Im headed to the rack, Ill check up here in the morning. Suprisingly, in the beginning of the post,someone said brakes dragging. Hadnt thought of that, so thats my project for tomorrow.
Old 08-16-2010, 11:16 PM
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You've got 84K on your car. Do you have the original O2 sensor? A sensor on it's way out can cause symptoms like that without throwing a code.

Also, have you changed the fuel filter? I had a car that would fall right off the power band because of a mostly-plugged fuel filter. That didn't throw a code, either.

And if these things dont' cure it, it wouldn't hurt to change them anyway if they're the original parts.

The message here is to start with the simplest, most obvious answer.
Old 08-17-2010, 12:17 AM
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didnt even think about the o2 sensor. Guess it would make sense after putting on a new high flow cat. WOuldnt hurt to swap it.
Old 08-17-2010, 05:12 AM
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what are your fuel trims running? It's prob just me but I'd say your exhaust is killing your low end too. 3' is to big. when I had my GTP. I had 3.2" pulley, ported TB, cam, headers, 2.0 AFC the whole 9 yards, yet when I went to a 3" exhaust I lost a lot . I couldnt even beat a 6 banger mustang off the line. Went to a Borla cat back and it made a huge difference. But with running that high boost sounds like something is clogged. I would check your air/fuel ratio then scan your LTFT to see if your injectors are ok, might have a bad one, clogged, to small ect.... then check your fuel pump. I had to get the hot wire kit for mine so it could keep up.
Old 08-17-2010, 07:01 AM
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If all else fails call Paul at PRJperformance, you'll have to look the number up online. He's a guru of the 3800.
Old 08-17-2010, 09:04 AM
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There are lots of great suggestions in here, you need to check or do all of them.

Or scan your car and post some logs too.
Old 08-17-2010, 11:03 AM
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I knew I shoudve posted here in the beginning. I have alot to check now. I appreciate the help from everyone. Ill post soon and let you guys know the results.
Old 08-17-2010, 01:21 PM
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oil change?
i say the temperature changes and maybe the torque management has something to do with this..
Old 08-17-2010, 02:42 PM
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supercharger belt slipping??
Old 08-17-2010, 04:40 PM
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I dont think the supercharger belt is slipping but it is an option. At this point I wont rule anything out. And as for the torque managment, how would I check if thats got something to do with it? I just got through w my brakes. I need to go add some fluid and see if thats helps any. Honestly I dont think that had anything to do with it, but I did need to do them.
Old 08-17-2010, 04:41 PM
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o...and I just changed the oil a couple weeks ago. Im pretty ocd about that, and use high mileage synthetic.
Old 08-17-2010, 06:21 PM
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Not to contradict anything my fellow LS1tech members have said, but I don't think that temperature or torque management can account for the change you've experienced. Something in the car is different than it was before, so you should be able to narrow it down to the 3 basics:

1. Air
2. Fuel
3. Spark

The first one is easy...You're still breathing and the car still runs, so you know it's getting air. Is the air filter clean? Anything obstrucing the intake? That's really about all I can think of for that.

Fuel is a bit more difficult. As I mentioned before, has the fuel filter been changed? It could be plugged. The fuel pump could be on the way out, too. Maybe you could buy or borrow a a fuel pressure gauge and see if you get adequate pressure under boost. It's also possible, though unlikely, that it may be an injector problem. That would be the last thing that I would check, if everything else is okay.

For Spark, it's pretty basic. How are the plugs? Did you pull any to read them? That can give you insight into the two things above. Are they black and sooty or are they whitish and/or pitted? The clues are there. How are the ignition wires? Have they been changed? Did you check them for resistance with a meter? Lastly, are you on the original coil pack? My Grand National, at one point, was way down on power. I traced it to the ancient factory coil pack that had trouble carrying load around 4000 RPMs or more. I would find out what the specs are for your coil pack and check it with a meter. Also, it would be advisable to check the ground wires for the engine, as a bad ground can have an impact, too.

Lastly, you may want to check the function of the boost solenoid and bypass-valve. These would obviously have an impact on the way power is created in your motor.

As I said before, check the BASIC stuff before you get into the exotic things (torque management, etc.) mentioned earlier. Even if none of the specific things I mentioned are the cause, troubleshooting using the parameters I described will most likely lead you to the root cause.
Old 08-17-2010, 06:47 PM
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With 85,000 miles on your trans it could be slipping. The trans in my 04 CompG was slipping at that same mileage, so I traded the car in for the G8 I have now because I knew it was a matter of time before it went out.
Old 08-17-2010, 06:51 PM
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same reason why i got the GXP but my comp had 150k
Old 08-17-2010, 07:05 PM
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Could vapour lock be a possibilty. Also the converter could be on its way out, they can rob an incredible amount of power if they're plugged.
Old 08-17-2010, 08:33 PM
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I have an itching feeling my tranny needs to be deeped sixed. Im thinking I just need to dog the **** out of it till it just goes while warranty still covers it. ZZP have a nice built one for a reasonable price. As for air, just super cleaned the air fliter 3 days ago, tomorrows project is fuel filter and blower belt. The plugs are less than 8 months old, so the basics have been covered. I want another Trans Am, actually, Firehawk so bad I can taste it, but Im still about 1200 upside down in the GP. Itll come soon enough, but for now its catching up from the 3 back surgeries Ive had till I can get something I know about. I love my GP, but my rwd 6spd V8 is my addiction.
Old 08-17-2010, 09:08 PM
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Get your trans h: http://www.tripleedgeperformance.com/
Old 08-18-2010, 05:28 AM
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Do you have a scan tool?
Old 08-18-2010, 01:00 PM
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dont have a scan tool....but I did just discover the only fuel filter on this car is inside the tank. How often does this need changing? Ive even heard theyre not a servicable item. hmmm
Old 08-18-2010, 01:18 PM
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your correct on the fuel filter. it is in the tankand un-serviceable I would try to find a scan tool off a locl club member and get a couple scans and post them up so we can see that aspect of what is going on.


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