5.3L Idle Vibration/Rough Idle Surge

Silverado-Hareek · October 9, 2014

11,800. After they did the TSB for the idle vibration it was about 85% better. Considerably less vibration while idling. But ever since I had the misfires and a spark plug replaced when it idles it vibrates and it almost worst than it was. And it comes in waves, the rpms flutter around 500 and if it goes under 500 the vibrations are stronger.

That almost sounds like the flow of fuel might be restricted if it's vibrating worse along with the RPM's dropping. I think you've said this before but you use Top Tier gas right? Maybe also try running a bottle of Techron through the system to see if that cleans anything up?

fondupot · October 9, 2014

Yea I use Shell mid grade 89 almost exclusively. If it's not Shell, its BP 89 or Mobile 89. Thought about getting some Techron. I'll get some tonight. My tank is almost empty so I'll add it on my next fill.

Edited October 9, 2014 by fondupot

hotrodz37 · October 9, 2014

That almost sounds like the flow of fuel might be restricted if it's vibrating worse along with the RPM's dropping. I think you've said this before but you use Top Tier gas right? Maybe also try running a bottle of Techron through the system to see if that cleans anything up?

Yea I use Shell mid grade 89 almost exclusively. If it's not Shell, its BP 89 or Mobile 89. Thought about getting some Techron. I'll get some tonight. My tank is almost empty so I'll add it on my next fill.

Fondupot, this is the same thing I'm experiencing, almost feels like a misfire, but no codes or anything. Funny you guys mention this, but I literally just ran out during lunch today and grabbed some Techron at Autozone. Not sure if you have Autozones where you live but the smaller bottles are on sale right now for 2 for $8. I am thinking mine is fuel related since it never did it before. I put both bottles in (treats 12 gal each) and filled up with 3/4 tank of Mobil so it would be more concentrated. Hopefully it blows whatever in there out and it will return to normal. I have a feeling these direct injection engines are pretty sensitive to buildup. I also got some dielectric grease while I was out and plan on pulling all the spark plug boots off tomorrow and making sure they're secure etc. Will report back if I see any improvements!

fondupot · October 9, 2014

Roger that. I have an Autozone nearby my house. So I will be doing the same thing tonight.

Silverado-Hareek · October 9, 2014

I have Autozone right by my house as well so if this works for you guys, I'm going to start running it every oil change from here on out. Originally I didn't think it would do much in a DI engine but if this helps, I'll definitely start using it. Keep us posted.....

hotrodz37 · October 9, 2014

Roger that. I have an Autozone nearby my house. So I will be doing the same thing tonight.

I was also thinking on the drive home that if it happened after you had a new spark plug put in, you might want to check the gap on it. You might have already but just something to check if you haven't already.

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fondupot · October 9, 2014

I was also thinking on the drive home that if it happened after you had a new spark plug put in, you might want to check the gap on it. You might have already but just something to check if you haven't already.

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I didn't personally check the spark plug gap, I assumed the dealership would be able to get that detail correct. But I think it was cylinder 7, Ill have to check my paperwork, but that would be on the driver side last cylinder? All the way on the firewall? If so...thats a a pain in the ass....

Edited October 9, 2014 by fondupot

fondupot · October 13, 2014

So I've been running this tank of gas with the two bottles of Chevron Techron (about a 1/4 tank in). Motor seems to idle a little better, less vibration and surge. My guess is there was some carbon buildup from the misfires/pinging/knocking I had a few weeks ago. But regardless I made an appointment at the dealer for Wednesday. I am going out of town this week on business until Saturday, so I told my service guy they could look at it again this week.

Also, last time they did my oil change/tire rotation I get a little front end pull. Prolly a tire going bad (not surprised, damn Goodyear SRA's) because I didn't notice it before they rotated the tires OR the time before that. We shall see what the dealer tells me about that...

Oh and not to mention my leaf springs were creaking like a bitch this morning. It was pretty moist out, heavy fog, light rain. They were SO loud.

Edited October 13, 2014 by fondupot

Silverado-Hareek · October 13, 2014

So i've been running thios tank of gas with the two bottles of chevron techron (about a 1/4 tank in). Motor seems to idle a little better, less vibration and surge. But regardless I made an appointment for Wednesday. I am going out of town this week on business until Saturday, so I told my service guy they could look at it again this week.

Also, last time they did my oil change/tire rotation I get a little front end pull. Prolly a tire going bad (not surprised, damn Goodyear SRA's) because I didn't notice it before they rotated the tires OR the time before that. We shall see what the dealer tells me about that...

Oh and not to mention my leaf springs were creaking like a bitch this morning. It was pretty moist out, heavy fog, light rain. They were SO loud.

Nice keep us posted on further Techron developments.

And yes my rear leafs are starting to sound like a marching band back there. I'm going to bring it up at my next oil change to see if they'll swap them out

14SLTZ71 · October 13, 2014

Why fuel additives don't work in direct inject engines.

The problem is carbon deposits are building up on the inlet side (top) of the intake valves. The deposits create turbulence and can restrict airflow into the cylinders causing performance and driveability problems (hesitation, stumbling, misfiring, even hard starting). The thicker the carbon deposit buildup on the valves, the worse the driveability problems.

GDI sprays fuel directly into the combustion chamber so the fuel completely bypasses the intake valves. Consequently, detergents and cleaners that are added to gasoline to prevent intake valve deposits from forming in port fuel injection engines never have a chance to do their job in a GDI engine. The inlet side of the intake valves are never in direct contact with the fuel so the detergents cannot wash away the deposits. Because of this, fuel detergent additives that are either in gasoline from the refinery or are added to the fuel tank have almost no effect on preventing or removing intake valve deposits in GDI engines. The additives work in regular fuel injected engines, but not GDI engines. I are you guys

http://www.aa1car.com/library/intake_valve_deposits_gdi_engines.htm

Edited October 14, 2014 by 15LTZZ71

hotrodz37 · October 13, 2014

So I've been running this tank of gas with the two bottles of Chevron Techron (about a 1/4 tank in). Motor seems to idle a little better, less vibration and surge. My guess is there was some carbon buildup from the misfires/pinging/knocking I had a few weeks ago. But regardless I made an appointment at the dealer for Wednesday. I am going out of town this week on business until Saturday, so I told my service guy they could look at it again this week.

Also, last time they did my oil change/tire rotation I get a little front end pull. Prolly a tire going bad (not surprised, damn Goodyear SRA's) because I didn't notice it before they rotated the tires OR the time before that. We shall see what the dealer tells me about that...

Oh and not to mention my leaf springs were creaking like a bitch this morning. It was pretty moist out, heavy fog, light rain. They were SO loud.

Yeah, I have only gone through an eighth of a tank since I filled up and added the techron, idled smooth yesterday for most of the day. On the way home I got on it a few times and today it's idling rough again. Wondering if I'm just beginning to blow the stuff out? I don't drive a whole lot (3k miles in 7 mos) so the carbon buildup paired with ethanol and not being driven a whole lot probably isn't helping matters any. I let it run in the driveway for a few min after I got home from work and it was surging and vibrating pretty good again. It will probably take the whole tank for me, hopefully this solves it.

Edited October 13, 2014 by hotrodz37

Retired Bob · October 14, 2014

Rough idle or vibration:

http://sandyblogs.com/techlink/?p=3780

Also saw this:

Condition
Some customers may comment about a squeak noise coming from the rear of the vehicle. During normal operation, certain vehicles may exhibit a squeaking noise that may be traced to the rear leaf springs. While this noise is an operating characteristic of leaf springs, the frequency and severity of this noise will be affected by the roads that the vehicle is driven on.

Cause
This condition may be due to debris getting between the leaf springs.

Correction
To correct this condition, lubricate the rear leaf springs using the following procedure.

Important: It has been found that the application of grease to the rear leaf springs does a better job of preventing the noise from reoccurring than replacement of the spring.

Raise the vehicle on a frame lift-type hoist.
Inspect the springs for damage. If none is found, proceed to the next step.
Pressure wash the rear leaf springs to remove as much dirt and grit as possible.
Dry the springs with compressed air.

Apply a liberal amount of grease, P/N 12345996 (in Canada, use P/N 10953501), under the front and rear tip inserts for the #2 and #3 leaves, on top of the tip inserts, and in between the #1 and #2, and #2 and #3 leaves, as indicated below. A screwdriver can be used to gently pry up the tip insert; however, a rag around the screwdriver must be used to prevent damage to the spring. Use a flat-bladed tool, such as a gasket scraper to properly distribute the grease.
Lower the vehicle to the ground and test drive to verify the repair.
Please inform the customer that this will offer relief, it is by no means a lifetime repair. Periodic cleanings and grease re-application may be necessary throughout the life of the vehicle.

fondupot · October 14, 2014

Rough idle or vibration:

http://sandyblogs.com/techlink/?p=3780

Also saw this:

Condition

Some customers may comment about a squeak noise coming from the rear of the vehicle. During normal operation, certain vehicles may exhibit a squeaking noise that may be traced to the rear leaf springs. While this noise is an operating characteristic of leaf springs, the frequency and severity of this noise will be affected by the roads that the vehicle is driven on.

Cause

This condition may be due to debris getting between the leaf springs.

Correction

To correct this condition, lubricate the rear leaf springs using the following procedure.

Important: It has been found that the application of grease to the rear leaf springs does a better job of preventing the noise from reoccurring than replacement of the spring.

Raise the vehicle on a frame lift-type hoist.

Inspect the springs for damage. If none is found, proceed to the next step.

Pressure wash the rear leaf springs to remove as much dirt and grit as possible.

Dry the springs with compressed air.

Apply a liberal amount of grease, P/N 12345996 (in Canada, use P/N 10953501), under the front and rear tip inserts for the #2 and #3 leaves, on top of the tip inserts, and in between the #1 and #2, and #2 and #3 leaves, as indicated below. A screwdriver can be used to gently pry up the tip insert; however, a rag around the screwdriver must be used to prevent damage to the spring. Use a flat-bladed tool, such as a gasket scraper to properly distribute the grease.

Lower the vehicle to the ground and test drive to verify the repair.

Please inform the customer that this will offer relief, it is by no means a lifetime repair. Periodic cleanings and grease re-application may be necessary throughout the life of the vehicle.

I've had them do the Rough Idle "recenter" procedure twice on my truck already. Both times it got slightly better, but not its back ask if it was never done.

fondupot · October 14, 2014

Why fuel additives don't work in direct inject engines.

The problem is carbon deposits are building up on the inlet side (top) of the intake valves. The deposits create turbulence and can restrict airflow into the cylinders causing performance and driveability problems (hesitation, stumbling, misfiring, even hard starting). The thicker the carbon deposit buildup on the valves, the worse the driveability problems.

GDI sprays fuel directly into the combustion chamber so the fuel completely bypasses the intake valves. Consequently, detergents and cleaners that are added to gasoline to prevent intake valve deposits from forming in port fuel injection engines never have a chance to do their job in a GDI engine. The inlet side of the intake valves are never in direct contact with the fuel so the detergents cannot wash away the deposits. Because of this, fuel detergent additives that are either in gasoline from the refinery or are added to the fuel tank have almost no effect on preventing or removing intake valve deposits in GDI engines. The additives work in regular fuel injected engines, but not GDI engines. I are you guys

http://www.aa1car.com/library/intake_valve_deposits_gdi_engines.htm

still cleans the fuel system, cylinders, spark plugs and injectors tho....

HondaHawkGT · October 14, 2014

Yeah the injector cleaner doesnt get the intake runners or valves but it definitely helped my idle vibrations. Ran silky smooth after a good highway run witht the stuff.