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Discussion Starter #1
I was having a friend follow me somewhere yesterday and when I got on it to go pass some one he said I was blowing black smoke out the back. I didn't notice it and have never noticed it before and it doesn't do it at idle. What could be going on? I change the oil every 3-4,000 mile since new and just got it changed. What can I check?
 

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GMC & IROC-Z
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348 Posts
According to his Sig, it looks like he has a 5.3L....Lots of smoke??? Is the engine running smoothly?
 

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Discussion Starter #4
It's running the same as it always has. And yes it's the 5.3l gas. If it was the diesel I'd be proud of the smoke.
 

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GMFS slowest truck :read:
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it could be a little darker than usual...prob just running rich at WOT.
 

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GMC & IROC-Z
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It could be the programmer, but I've never had mine do that. I wonder if your gas mileage has gone to crap, cause black smoke should be excess fuel.
 

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Its probably excess carbon build-up burning off. If you drive pretty easily most of the time not really revving the engine out and pushing it you probably had some carbon build-up on something in the combustion chambers. When you punched it the cylinder temps rose dramatically and that carbon was burned off.
 

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I'm on a mission
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richness problem possibly, if it's got some miles on it your valve seals could be going bad
 

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Discussion Starter #12
None at start up. The only time it was noticed is when I got on it. I got some Sea Foam and put it in the gas. I'm gonna put some in the brake booster tomorrow just to be on the safe side. And it's only got 46,000 mile on it.
 

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Discussion Starter #14
haha, sounds like your friend is FUCKING with you.

I've said it to buddies, they're like - hahaha yeah bullshit :imo
I thought about that but he's usually pretty serious about stuff. Especially when it comes to trucks.
 

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Ballin' on a Budget
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Have you tried to reenact it and look for yourself? I know mine blows enough black smoke for me to see it out my rearview at wot, but i just assumed it was running rich (its blown w/ a bad tune) because mine doesnt eat any oil. Have you noticed it eating any oil?
 
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