'08 silverado rough idle

[treemedic]

hey! just bought a '08 3500HD w/ 6.0 vortec and 4.10 gears and my engine has idled roughly since i bought it. i have about 600 miles on it and have ran both 87 octane and prem. to see if that is the problem, but it doesn't help. check engine light does not come on and dealership says it's probably normal. i also have an '02 suburban that does the same thing... it's especially noticeable in gear, like at a stop light. please, someone tell me chevy knows how to make an engine that idles

[Airjer_]

Here's what I would due. Test drive another truck identical to the one you own. If it does the same thing than the problem is likely a characteristic of the vehicle and nothing will be down about it. Remember, it is a 1 ton chevy truck so it isn't going to feel like a European luxury car!

[ukrkoz]

1. did you run scanner on it?

2. run can of seafoam through tankful. best to get on freeway and give her about 30 min at 70mph right after you poured it in.


silvies idle just fine. sounds like regular dealership bs. keep in mind, their bread and butter is doing maintenance, not figuring out their manufacturer screw ups. and for pete's sake, IT'S UNDER WARRANTY. i'd turn it into manager's nightmare if he does not fix it.

[j cAT]

Originally Posted by ukrkoz

1. did you run scanner on it?

2. run can of seafoam through tankful. best to get on freeway and give her about 30 min at 70mph right after you poured it in.


silvies idle just fine. sounds like regular dealership bs. keep in mind, their bread and butter is doing maintenance, not figuring out their manufacturer screw ups. and for pete's sake, IT'S UNDER WARRANTY. i'd turn it into manager's nightmare if he does not fix it.

come on here , seafoam on a new vehicle ! this could be many things . have the dealer give the vehicle a complete inspection with the diagnostics hooked up...make them do thier job and keep the customer satisfied.

[treemedic]

i'm not expecting perfection...just a decent idler for $35,000. your right about typical dealer bologna, and i am prepared to thrust this truck into them deeply, but i've learned that they will have my truck for a couple of days, not figure anything out, tell me i have to run 87 octane 'top tier' gas so as not to booger up the computer, etc,etc, blah, blah, blah... that's why i'm here. you guys know infinite amounts more about these things through trial and error than the techs seem to. so thanks in advance. what is seafoam anyway... i thought it was a chocolate covered confection?

[treemedic]

if my check engine light has never come on will they have any codes to check?

[ukrkoz]

Originally Posted by treemedic

i'm not expecting perfection...just a decent idler for $35,000. your right about typical dealer bologna, and i am prepared to thrust this truck into them deeply, but i've learned that they will have my truck for a couple of days, not figure anything out, tell me i have to run 87 octane 'top tier' gas so as not to booger up the computer, etc,etc, blah, blah, blah... that's why i'm here. you guys know infinite amounts more about these things through trial and error than the techs seem to. so thanks in advance. what is seafoam anyway... i thought it was a chocolate covered confection?

well, CEL is part of emissions system, not quite related to other possible issues. so, go to any major parts store and have it scoped for free.

you have warranty? they should have loaner vehicle for you, bud. they made enough zoo-zoo on you to kiss your right foot along this. and five times in a row, btw.

as of J's remark about seafoam..... j's being j, you know. seafoam is a strong medicine. pure magic. one thing i know for sure, it will not HURT your $35K candybar. it might clean its sinuses, that's for sure, and it might be just that. i have driven with it in cranckcase for 2000 miles on one of my trucks, and it won't even sneeze. it's not your regular engine cleaner. six bucks plus tax is a good investment.

but hey, like i said - check codes 1st. we all might be surprised.

btw, what's your regular gas station? you ain't arcoing or circle k-ing, aye, mate?

Hi, my 2008 Silverado does the same thing. (1500 4x4, 5.3L iron block) Has about 300 miles and it had me guessing what it could be. Please update if you find the problem.

[j cAT]

Originally Posted by treemedic

if my check engine light has never come on will they have any codes to check?

It is possible that with the diagnostic computer hooked up the dealership tech will see what parameter is off....not a DTC...the computer will display analog readings of various componets this will help in location what device needs attention...


Of coarse if the dealership only has idiots working there your screwed..


on a vehicle with 600miles what is there to clean....this isn't dirty/deposits....this must be something defective or improperly installed...

give us a response when its resolved..