Vibration At Idle

[BillTodd]

Just bought a used 2009 Chevrolet with a 5.3 engine with 31,000 miles. It had new engine installed at 27,000. Since I purchased it, at idle it vibrates to a point you can feel it in the back seat. You can put it in neutral and it goes away. The dealership says it is normal. The dealership cleaned the fuel rail and it helped but, came back within a few days. They also told me to run top tier gasoline which I did but it did not help. Any idea what it could be?

[MaverickZ71]

I bought my '09 Silverado 4x4 (aluminum 5.3L, 6 speed, 3.42 gears) new in Jan. '10. Since then have run nothing but 'top tier' fuel in regular, mid-grade, and premium, with 2 bottles of Techron Fuel System Cleaner at each oil change, like it says in the owner's manual. At idle, especially in gear, it has always felt like it occasionally 'misses' and the idle speed 'hunts' back and forth around a band of a few hundred rpm. I've read where others have said their trucks do this too. 2 dealers say this is normal. It may be what GM calls "normal", but it is annoying, and may be a leading reason why my next truck may have a blue oval on the front. Kinda p1sses me off when my 32 year-old $11K car with a carb and distributor cap idles better than my new $40K truck with computer-controlled ignition and fuel injection!

[jdubub]

Mine does this as well. I think its just the character of these trucks. I dont think its hurting anything, its just annoying

[jro909]

normal...my 04 does it even

[BillTodd]

I bought my '09 Silverado 4x4 (aluminum 5.3L, 6 speed, 3.42 gears) new in Jan. '10. Since then have run nothing but 'top tier' fuel in regular, mid-grade, and premium, with 2 bottles of Techron Fuel System Cleaner at each oil change, like it says in the owner's manual. At idle, especially in gear, it has always felt like it occasionally 'misses' and the idle speed 'hunts' back and forth around a band of a few hundred rpm. I've read where others have said their trucks do this too. 2 dealers say this is normal. It may be what GM calls "normal", but it is annoying, and may be a leading reason why my next truck may have a blue oval on the front. Kinda p1sses me off when my 32 year-old $11K car with a carb and distributor cap idles better than my new $40K truck with computer-controlled ignition and fuel injection!

 

 

It is very annoying, just put a bottle of Techron in the gas it seems to have settled down. I guess this will be the norm til I get pissed again.

Thanks

[Cool Zr2]

Who cares? All trucks idle different. Hell, my 08 suburban starts weird at times, and idles funny, but I don't care, its not like someone is going to pull up next to me and my suburban and laugh like the bully on the Simpsons because it has a weird starting issue that won't go away and idles funny.....

[dataspng]

Normal - 2011 5.3L does it.. I just pretend it has a high performance cam in it...

[ktn65]

Normal - 2011 5.3L does it.. I just pretend it has a high performance cam in it...

 

 

You mean it doesn't!!

 

My 2011 5.3 is the same.

[flyboyron]

My 09 with the 5.3 has an idle problem also once in a while. As it warms up you can feel the truck is perfectly smooth and then all of a sudden it starts to shake for a couple of seconds, then smooths out again. It will do that about every 15 - 20 seconds as if the engine wasn't balanced correctly or something. I think it is the way it is programmed since it does it so regular. I just can't believe that they could make an engine, especially a V8 that is not smooth. When I had my 06 Honda Civic it had a 4 cyl in it and it idled smooth all the time. Oh, well, technology................can live with it..............can't live without it.

[Sly]

Who cares? All trucks idle different. Hell, my 08 suburban starts weird at times, and idles funny, but I don't care, its not like someone is going to pull up next to me and my suburban and laugh like the bully on the Simpsons because it has a weird starting issue that won't go away and idles funny.....

 

LOL! Your truck idles funny HA HA!

[jro909]

it idles rough from the pcm leaning out the fuel...thank the epa standards

[semper3318]

I have a 2010 (aluminum 5.3L) and it does the same thing. My RPM's will bounce a little sporadically when at an idle. I've had it to the dealer and they ran a relearn for the idle speed but this didn't help. Besides that they act like it's normal. I recently rented a POS kia minivan that purred like a kitten. It is pretty frustrating when a full size $40k new truck won't even idle correctly. Something isn't right causing this, I'm pretty sure GM didn't design these trucks to bounce from 500-700 RPM sporadically at idle shaking the cab. But like always the famous "it's normal" seems to trump any problems, probably because they don't have the slightest clue what it is and it would take a lot of troubleshooting. If anyone finds a solution for this please post on the board. It appears lots of other folks are having the same issue...

[knightr]

Must be one of the lucky ones, but my 4.8 WITHOUT afm idles so smooth I

sometimes don't know if it is even running. It's been like this since day 1, now

with 40,000 on it.

I think it says something about an iron block & no AFM.

[cmackvr6]

I just changed the oil in mine today and it smoothed it right out.

 

 

............ for now.

[00Silverado4x4]

Almost 90k miles on the '06 with all original equipment on the engine, no mods & never seen my idle bounce around as described here. I can't believe that idle bounce can possibly called "normal". The last vehicle I had that was fuel injected & didn't idle evenly needed a fuel filter replacement & then it was good as new.

To the OP sorry I have no suggestions except maybe have an idependent mechanic run a diagnostic to verify your "normal" condition.