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power surging 2004 gm 3800
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Discretesignals
Ultimate Carjunky
/ Moderator
Oct 2, 2013, 3:49 PM
Post #26 of 33
(1794 views)
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Re: power surging 2004 gm 3800
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I honestly can't see mufflers causing that unless they are causing some sort of excessive back pressure in the exhaust. You can measure exhaust back pressure with a gauge screwed into the O2 sensor bung if you want to confirm.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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repairdad
User
Oct 3, 2013, 1:21 PM
Post #27 of 33
(1776 views)
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Re: power surging 2004 gm 3800
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questioned mechanic about the data stream info and he reads no problem(s).
Two mufflers , still surging.
A lot of detail ain't getting me anywhere ( nowhere ).
Hate to get sarcastic but snow tires are not going to fix this problem either.
MAF swap next. TODAY
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repairdad
User
Oct 5, 2013, 1:32 PM
Post #28 of 33
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Re: power surging 2004 gm 3800
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MAF swapped . Still surging .
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repairdad
User
Oct 5, 2013, 8:47 PM
Post #29 of 33
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Re: power surging 2004 gm 3800
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Not a great deal of coolant consumption but since I did bleed the air out at the brass needle valve on top of tstat elbow when refilling a few weeks ago now and there is some topping up required ( had to replace original clamp with a real screw clamp ) I put IRON TIGHT in the rad. Not Bardol , pepper or some other concoction. This product works on small coolant leaks. I was / am grasping at the possibility of a head gasket issue. Coolant being sucked into combustion chamber(s). Again grasping as problem such as this would be more over all RPM and load conditions or at least not so debilitating as to cause this very obvious drop and rise in the power output at 1800+_200 RPM on a slight grade when warm. No surging when 1st started in 70 deg f. But as soon as temp starts to rise on the dash gauge it appears.
going back over these posts 1) The TAC system is redundant in that it uses two TPS sensors and two APP sensors.
Redundant means possible conflict. So I want to assume that there would be OBDII code generated but what I want is a definitive root source of this up and down of the power output to the wheels. Again this is a series III and I see one TPS on a simplified butterfly throttle actuated by a stepper motor. Yes the cruise control that no longer works did try to hold the speed but this surging was the same as there was and is little speed loss and as peddle pressure eventually @2000 RPM it stops. I did question the possibility of a software issue but mechanic suggested otherwise.
Starting to drive this car harder as the solution seems to be drive it and make it worse . New oil,transmission dex6,coolant and lets see what blows up first.
Electrical issue ? There is a load RPM change when air-condition etc. is turned on and off. This seems to be a predetermined amount and all vehicles seem to boost up RPM as to not stall out at idle. 200-300 RPM at idle . What about 200-300 RPM cutting out at 1800 RPM (not at idle RPM range). This surging happens with and without A/C on.
(This post was edited by repairdad on Oct 5, 2013, 8:53 PM)
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Discretesignals
Ultimate Carjunky
/ Moderator
Oct 6, 2013, 9:08 AM
Post #30 of 33
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Re: power surging 2004 gm 3800
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Don't know what to tell you. There was a post in here I believe for an update to the PCM's software for your symptoms, but I don't know where it went. You could be chasing a bunch of ghosts if all that is wrong with it is some software glitch that can be resolved by an updated calibration.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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repairdad
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Oct 6, 2013, 9:16 AM
Post #31 of 33
(1723 views)
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Re: power surging 2004 gm 3800
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Nice. Would that be something only a GM dealer can do ? -------------- This is not just the on board start with 8hrs+ off + A/C in drive etc. as it does that ok , or at least at idle condition only.
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Discretesignals
Ultimate Carjunky
/ Moderator
Oct 6, 2013, 9:34 AM
Post #32 of 33
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Re: power surging 2004 gm 3800
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Software glitches are hard to find for a tech, if there is one. I am not saying that an update may solve your issue, but if there is a TSB floating around that matches your symptoms that can be corrected by an updated calibration, that is the first place I would go. You could spend costless hours and money trying to fix a problem that a software glitch is creating.
Dealers can check for updates and do reflashes if the vehicle doesn't have the latest and greatest. Some independent shops may have the equipment to flash control modules. You'll have to do some looking around in your area. Just remember that it may or may not resolve your issue, but it is one thing to eliminate. If you do find a shop that does reflashes, have them check your vehicle out and see what their opinion is.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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repairdad
User
Mar 8, 2014, 6:22 PM
Post #33 of 33
(1625 views)
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Re: power surging 2004 gm 3800
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Good Day
I regret to inform you that the surging just stopped. No assignable cause. Really wanted to post a definitive fix for this fault. Sorry but after two weeks of regular fuel this problem has not returned.
Only thing I did was get fed up and with -15 C nights I just pounded 100% throttle on dry pavement. Slipped sputtered chugged every time for a week of cold night hammering the poor thing. Normal running with the surge after up to a warm temp. After this repeated cold start 100% throttle on dry pavement load. I surging stopped. Why I really think a rued awaking under these relatively extreme cold conditions would cause this persistent problem to stop is beyond me.
What I did do (as I had done back in Sept.) in response to this sputtering/chugging when really cold was fill with premium fuel and Lucas. The last thing I wanted was another problem to go with the surging.
Now I do not ever promote driving a vehicle hard when very cold ( do not care what additives you have in the oil or fuel ) . This flat out loading on the drive train worked.
Thank You
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