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Rough Idle / engine vibration on Idle Seirra 2008 vortec 5.3

mike66

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mike66 Enthusiast

mike66

Posted
Posted

Purchased my 1st truck GMC seirra 2008 5.3 vortec. When stopped I nolticed that the idle is very rough, and the truck almost shakes, its worse in the mornings, no codes on display , took it to a shop here in calgary and they did a throttle body service , still no difference , booked it for a check up with the dealer next week, truck is under power train warranty, any tips or knowledge on this topic would be appreciated is this is normal with this type of model ?

Thanks in advance.

spock Enthusiast

spock

Posted
Posted

I have a similar issue. Read many posts about it being things like the gas blend to the pcm leaning out the mixture. It's an annoyance for sure but it runs so good otherwise I've gotten used to it.

  • 1 month later...
Mr_Rooney Enthusiast

Mr_Rooney

Posted
Posted

 

I too have had this problem and Saturday I recieved a letter from Chevrolet. The second paragraph addresses the problem.

 

 

"This letter is intended to make you aware that some 2008 model year Chevrolet Silverado vehicles, equipped with a V8 engine, may have a condition where the throttle position sensor may cause the engine to run rough and cause the malfuntion indicator lamp and/or an Engine Reduced Power message to illuminate. If this occurs, it could result in reduced engine power."

 

 

I have had the Engine Reduced Power message 3x last year in cold weather never in above 50 degree temperature. Rough idle, yes. More disturbing is the sudden jump in acceleration from a stop. I do not mean unintended out of control acceleration, just a lag between peddle input and response. And the response is like a step function.
SnakeEyeSS Senior Enthusiast

SnakeEyeSS

Posted
Posted

Makes you wonder what happens with these single model year glitches. Especially when they aren't the first year of production.

j-ten-ner Senior Enthusiast

j-ten-ner

Posted
Posted

@ mike66

 

My truck is 07 Sierra 5.3. I've experienced rough idle too.

And sometimes spluttering while accelerating.

I checked and changed the spark plugs and the truck runs fine again.

And the lifter ticking I could hear before was fixed as well. Turned out to be a lose plug... :rolleyes: .

 

Maybe is worth it to check on your plugs and wires before you give it to the dealer for big bucks.

 

so long

j-ten-ner

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