Shudder at light throttle

[Vegasmarc21]

Can anyone tell me what shudder I have under very light throttle usually on any gear EXCEPT 1st and 2nd gear with about 1100 rpm to 1500 rpm..... Doesn't happen when I start driving when Tahoe is cold and not up to operating temperature. WOT there is no shudder at all. I have a 2011 Tahoe 5.3 V8 with hundred twenty thousand miles.

 

[PG01]

You rver clean the tb?

 

[Vegasmarc21]

You rver clean the tb?

Yes.....twice. the 1st time I was too careful, as in just the outside part, second time, I cleaned it to sparkling, brand new looking condition. I also cleaned MAF sensor 2 twice.

I was trying to clean the idle air control, but sounds crazy, I can't find it. I'm not a mechanic, but I can do basic tune ups like oil changes, radiator flushes, spark plugs, and just installed an exhaust manifold clamp on the driver's front and passenger rear which was a pain in the rear.
I was thinking the same, throttle body but the shudder only happens was vehicle is warmed up and in 3rd gear on up.... The weird thing is that it will go 2 or 3 days running smooth, then all of a sudden it comes back.

 

[PG01]

Hows trans fluid look/level? Last service?

 

[Danny3737]

Any cracked or brittle vacuum hoses?

 

[Vegasmarc21]

I bought the 2011 Tahoe 5.3 2 months ago. Checked the fluid and even had a reputable big time transmission shop here in Portland Oregon look at the transmission fluid. They said it looks fresh. I also found out through a car fax type of vin search that the transmission fluid was just changed a month before I bought it. I don't see any brittle hoses or cracks in any vacuum lines..... I'm hoping it could be a bad throttle body or throttle body sensor or pedal sensor or dirty fuel injectors... It runs great wot and idles pretty smoothly....I do have a little slack on the driver's side cv axle...2 months of this wondering what it could be..... Is it the v4 mode that makes it shudder? I did have a 2004 z71 5.3 that was so smooth.... You would think GM would be at this point building off of that, making Tahoes as good or better nowadays.... Anyone help I'm getting sick of this shudder. I want to get a tune and some nice replicas, but not until this shudder is solved....I did replace with new ngk iridium's and MSD plug wires....

 

[Meccanoble]

I was going through same mess as you trying to find this issue and still have it.

I changed the spark plugs
I got a tune to remove the v4
I already changed the tranny fluid over 6 months (15k+ miles) prior to noticing the shutter
Cleaned throttle body/MAF

Dealership thinks its torque converter or related. I would love for it to be something along the lines of throttle body but who knows.

 

[Vegasmarc21]

I was going through same mess as you trying to find this issue and still have it.

I changed the spark plugs
I got a tune to remove the v4
I already changed the tranny fluid over 6 months (15k+ miles) prior to noticing the shutter
Cleaned throttle body/MAF

Dealership thinks its torque converter or related. I would love for it to be something along the lines of throttle body but who knows.

Off the topic, what tune did you get?

 

[Vegasmarc21]

One interesting note here, though I check the transmission fluid, and although it seems brand new and not burnt, it is way over filled. The cold Mark is below the hot Mark, and when I check it cold, it's about 2in above the hot Mark..... Could this be part of the shudder at low RPM? I bought it used from a Ford dealership, so I'm thinking that a Ford Tech or whoever changed it didn't go through GM procedures.

 

[Meccanoble]

Off the topic, what tune did you get?

Vengeance Racing tune. Its a local shop in GA that works on domestic cars. They have ability to turn off the v4 so the engine mechanisms are still there but the v4 wont function. Similar to the device people plug into their car to turn it off but cheaper and more permanent.

I thought I slightly over filled mine but when I checked, it was actually a little low. When I put enough in, the shutter got better but still exists. Before, I would have to take my foot off the gas or accelerate significantly harder to make things better. Otherwise it would cause a lot of vibration from shutters. Now, you can still feel the shutter and see it in the rpm's but keeping the same pressure on gas, you can see truck fight through it and drive somewhat normally through the shutter. I changed my oil the other day and checked the tranny pan for leaks and on ramps, you can see 1 or 2 of the rear center bolts is a little wet as if there is a slight leak. I didnt want to tighten the bolts too much but may have to give them a half a turn to be safe, atleast the rear ones.