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Clearing Up Some Slight Rough Idle Issues.

jerseydrew

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jerseydrew Enthusiast

jerseydrew

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well i have had a slight rough idle since i got the truck almost a month ago. dealing with a few other things on the truck first i finally got around to dealing with this. first thing i did was run some fuel injector cleaner through it about a week ago and that did nothing. so i pulled a plug today to see how it looked and that looks fine for 40k miles, maybe just a touch of oil in the cylinders because there is some slight accumulation on the plug but no big deal. i also took the mass air out and sprayed it down with the appropriate cleaner and also used the same stuff (cause i didn't have anything else) to wipe off the slight crud on the throttle body. when i opened the throttle body i did notice a little bit of caked on crud in there. i started the truck and it is definitely better but not good yet. i think tomorrow i will seafoam it and see how it turns out. if that helps but i am still not satisfied i will replace plugs. i think the seafoam will do the trick though cause i have already seen an improvement from just cleaning it up a little. i may even bye some TB cleaner just to clean that up the right way.

jerseydrew Enthusiast

jerseydrew

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Good luck with your fix. Check the engine mounts too as they can cause some engine vibration. You should never be able to feel your truck idle or there is a problem.

 

 

i will check those as well and if they are bad i have CPO so woo hoo...

jerseydrew Enthusiast

jerseydrew

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engine mounts look fine, did the ebrake test. and i did the seafoam today and it is almost fully cleared up. i think i am gonna do the plugs just to take the doubt out of my mind and that's about it.

jerseydrew Enthusiast

jerseydrew

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ok i have now run the fuel system cleaner, seafoam, cleaned the MAF and TB, check motor mounts and changed the plugs (which by the way the one near the firewall on pass side is a PITA!) and the rough idle is still there. it is not as bad but it is still there.

 

anything else to look into or maybe i am just looking for something and this just may be the way it is?

jerseydrew Enthusiast

jerseydrew

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well today i confirmed that i was chasing a ghost. today was the first time i was able to ride in my buddy's BRAND new Tahoe with the 5.3 and the idle is EXACTLY the same as mine so now at least i know it is just the nature of the beast.

 

i may not like it but at least my mind is now at ease.

sab316 Enthusiast

sab316

Posted
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Yeah my old truck had a little shimmy to it at idle ( '01 Silverado with the 5.3) and my new truck has the same thing ( '09 with the 5.3). Was in a buddy's '07 Silverado with the Vortexmax the other day and he also had the slight shake at idle. I don't think its anything to worry about.

4wd Enthusiast

4wd

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When I had mine brand new it was idling little rough for months, rpm fluctuating but after a while it almost disappeared. So I guess it is nothing to worry about (at all). Remember dealer kept saying FUEL FUEL FUEL, I think it is the programming, or it could be designed to run like that to save fuel at idle!.

Reject Enthusiast

Reject

Posted
Posted
Yeah my old truck had a little shimmy to it at idle ( '01 Silverado with the 5.3) and my new truck has the same thing ( '09 with the 5.3). Was in a buddy's '07 Silverado with the Vortexmax the other day and he also had the slight shake at idle. I don't think its anything to worry about.

 

 

My VortecMax shakes a little at idle, almost like it has a cam in it.

nickvrebel Senior Enthusiast

nickvrebel

Posted
Posted
Yeah my old truck had a little shimmy to it at idle ( '01 Silverado with the 5.3) and my new truck has the same thing ( '09 with the 5.3). Was in a buddy's '07 Silverado with the Vortexmax the other day and he also had the slight shake at idle. I don't think its anything to worry about.

 

 

My VortecMax shakes a little at idle, almost like it has a cam in it.

 

it does have a cam in it! :thumbs:

 

on a more serious note, GM has, over the years, gotten a little more aggressive with their factory cam specs and tuning. This is where the HP/ torque gains come from when you look between the 1999 5.3 and current. The thing they try to do is keep a smooth as possible idle while achieving more power. In most aftermarket situations the customer could care less about a smooth idle, a nice choppy cam makes more power and that's what it takes to get there. GM of course will never put a "choppy" cam from the factory b/c the average Joe Customer doesn't want that.

4wd Enthusiast

4wd

Posted
Posted
Yeah my old truck had a little shimmy to it at idle ( '01 Silverado with the 5.3) and my new truck has the same thing ( '09 with the 5.3). Was in a buddy's '07 Silverado with the Vortexmax the other day and he also had the slight shake at idle. I don't think its anything to worry about.

 

 

My VortecMax shakes a little at idle, almost like it has a cam in it.

 

it does have a cam in it! :thumbs:

 

on a more serious note, GM has, over the years, gotten a little more aggressive with their factory cam specs and tuning. This is where the HP/ torque gains come from when you look between the 1999 5.3 and current. The thing they try to do is keep a smooth as possible idle while achieving more power. In most aftermarket situations the customer could care less about a smooth idle, a nice choppy cam makes more power and that's what it takes to get there. GM of course will never put a "choppy" cam from the factory b/c the average Joe Customer doesn't want that.

 

 

Interesting, actually when I had this rough idle one technician was telling me this running like race cars, other time he was saying this is corvette engine, you could see it, the engine would almost like to die!, then it picks up again, the take off was quicker.

 

what is the risk of putting aftermarket cam later! (after warranty)?

jerseydrew Enthusiast

jerseydrew

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My VortecMax shakes a little at idle, almost like it has a cam in it.

 

my z06 has a cam in it and this is NOTHING even similar.

 

 

Jerseydrew, is yours a GMT-900? Where did you put the seafoam through?

yes 900. i removed the large vac line off the brake booster. you have to pull it off and set it lightly on the barb again so the truck will start. then with engine fully warm and running, you want to remove the hose from the booster and plug it immediately with your thumb. then with the 6 ounces of seafoam ready in a small bowl you get it real close and then let the engine vacuum just suck it in the line. once the seafoam is done put your finger over the end of the hose again so it will still run for a few seconds. then just let go and turn the truck off for 5 minutes. once you restart i hope you have the truck outside cause the smoke this stuff makes is incredible.

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