2006 Chevy Silverado 2500HD Rough Idle

[felipemolina]

Hello to all, I am having an issue with my 2006 Chevy 2500HD, sudendly start rough at idle, but when I increase the RMP the rough go away, and descelerate and rough back again, sounds a lot of backfiring also. Any suggestion ??,

Today I am thinking to check each coil pack, and check in the injectors.

 

Please any help is appreciated!

 

Thank in Advance

[dewfpo]

Is the MIL (check engine light) lit? If it is, you can get the codes read for free at most any chain auto parts store.

 

DEWFPO

[Swimmer8366]

When this happened to my 2002 it would random cylinder misfire while idling in your case I would start by cleaning the throttle body if that doesn't do it fill one of your cylinders with compressed air and watch the coolant reservoir could be a head gasket if coils plugs and injectors work properly. Good luck to you.

 

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[Formulabruce]

Yup clean the throttle body WITH Throttle body cleaner, and do it well. Air box has to come off. Will cause this problem without an engine code

[Swimmer8366]

I would use a full induction cleaner and really clean the hell out of her. It'll get the intake the throttle the injectors everything if done properly. Back when I worked for Toyota castle made a killer induction cleaning system and grill used it regularly on everything. With lots of good results.

 

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[felipemolina]

Thanks to all for replay, so far, I already check the coils---OK!, clean all injectors---OK!, new spark plugs, new cables, clean the throtle body really good, clean the MAF, unfornunatelly I still have the issue, today I will check the fuel pressure (to make sure is not the pump), but I have a question, when I was releasing the fuel pressure from the port, fuel was coming out, but suddenly I saw only air, is that a really simptom for vaccum air leak in the system right ?.....I will try to do the smoke test today also to see if I can find any leak....I will keep you post....,TIA

 

 

dewfpo, yes I did scan the codes, DTC-0101; DTC-0300, and autozone recommend change the MAP sensor, but I tested and the device work properly.

 

Swimmer8366, I hope I can find any leak on the manifold and not on the head gasket.

[Formulabruce]

On a side note, I would put "Copper" never seize on the spark plug threads... Dont use aluminum on the Aluminum heads, needs dissimilar metals. Plug can and do break off .

[Swimmer8366]

I use high temp wheel bearing grease on my plugs not anti seize.

 

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[felipemolina]

Update!, Finally this last weekend my Truck is like new again, I did not have any vaccum leak, was a little bit worst, I found a broken spring on valve chamber 4, and it was making the motor on that lean condition. After I replace, so nice! Thanks for your help.