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Discussion Starter · #1 ·
This is my first post... so here it goes. I just bought a 2007 classic 2500 duramax cc/sb. Has 56000 miles on it. Iv always been a chevy person. I traded my 2005 2500 cc/sb gas in on the 07. Alot of my friends have diesels. Iv been around them and riden in them plenty. For the last several days iv had no issues with mine. The truck is very clean and is GM certified! Last night we went out and all rode in my buddys truck. A 2007 cc/sb. Same package as mine and all. Well while riding i noticed his truck seems to shift better than mine and he seems to have alot more power. Both trucks are completly stock. COMPLETLY. My truck has a few hard shifts every now and then. Now iv been baby it because iv waited so long to get a diesel. I havent even let my dog in the truck yet. And forget the kids getting in yet. LOL. It almost feels like im towing something...kinda? it just does not feel like i have the power he has. Also the black smoke! we were getting on the highway the other day and he got into it and black smoke was pooring out. Mine doesnt do that?
Any ideas? its still under warranty. But i want to go in with some kind of knowledge of something to tell them to look at.
Thanks guys.:drink
 

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:welcome to the forum!!

I would start with changing the fuel & air filter. The tranny spin-on filter could probably be changed too.
 

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Welcome! Did your buddy buy his truck new? You said his poured black smoke. That sounds like someone has been playing with the tuning. Maybe he did behind your back (he didn't want to chance you being faster than him), or maybe someone before him. Does your buddy have a son who uses the truck? Maybe the son dropped a program in there. For sure change your filters, but maybe it's possible someone played with your buddy's truck.
 

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it just does not feel like i have the power he has. Also the black smoke! we were getting on the highway the other day and he got into it and black smoke was pooring out. Mine doesnt do that?
That means his either has a problem or it is tuned. You can re-flash the ECM with a tune and leave no visible evidence, my guess is he has it tuned. Your truck doesn't sound like it is doing anything bad, his just sounds like it is modified. Look around the EFI Live section of the forums and get a tune then tell him it is stock also and then blow his doors off...

Tyler
 

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Discussion Starter · #5 ·
so all of you say change the air and fuel filter... Even if i just drove it home from the dealer the other day? You all dont think they did that? Hell if thats the case what else should i do to make sure all is good?
 

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I never trust a dealer to do the maintenance even when I pay them. I always mark filters to know if they actually changed them.
 

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Check alamites to make sure everything is greased. Check tire pressures (including the spare!). A transmission fluid flush including inside and spin on filters would be a good idea, especially if you see transmission temps in the 200 range. Serpentine belt. Front and rear brakes. I would also look at your brake fluid to see if it is dirty. When you buy a used vehicle (I never buy new), you really should take it upon yourself to go through it pretty well to make sure you are starting out with a recently maintenanced vehicle.
 

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I've never seen a stock dmax that pours out black smoke like you describe. I think your friend's truck has been tuned!
 

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^^^^^ agree I would change the fuel filter as well do a tranny flush dont forget to change the filter on their as well, But before you flush the transmission fluid pull the dip stick and smell it make sure there is no burnet smell to it. Also if you havent already take the time to change your oil and your t-case fluid.

Hopes this helps
 

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that truck has to be tuned but who knows id go with what everyone is tellin ya fuel filter tranny spin on and maybe air filter. and up ur buddy witht 5 inch exhaust adn EFI or a decent canned tuner
 

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if your truck just seems sluggish after you have checked out filters, clean mass flow sensor makes huge difference. Biggest thing if you have been babying it like you said your tranny relearned itself as a baby. reset tranny run it hard and it will learn the different shift points and feel like a totally different truck.
 
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