Huge hesitation, mechanically inclined. Please help

[#1taho]

How's your air filter ? I have read only a few of the posts but I ask on the filter cause I changed my stock one for a cold air set up and no more hesitation

 

[Brian Wilson]

Air filter is new. It had a aftermarket tube when I bought it. I thinks it's called a modular intake tube. Basically a stock airbox with new filter and a straight plastic tube

 

[Brian Wilson]

I believe I will try and get into contact with justin again. I didn't want to buy the 600$ autocal but if it is better I guess it must be done. And I have already spent more than 600$ trying to fix this thing so I guess it's time

 

[MichaelSE]

Damn man, what a mystery. I'm sorry you're dealing with all this. Here's my idea, hopefully it leads somewhere. Take off the intake tube and have someone try various throttle positions (10%, half, WOT) while you watch the throttle plate. *Maybe* an internal issue with the throttle control motor is preventing it from opening to where it should for certain throttle position ranges.

I believe the ECM uses the actual pedal position to determine throttle input, so maybe that's why it looked fine on the computer.

Edit: I see that you replaced the TPS already so you may have already checked this. If so feel free to ignore my post!

 

[Brian Wilson]

No sir. Any help is appreciated. One guy told me my carb float might be stuck so..... no advice is bad advice. I have tried that but, since the position of the throttle plate is not exactly linear with flowthru, it's really hard to say if that it's the issue. I guess my next step is to swap the throttle body itself with my brothers denali while I wait for justin to get back with me.

 

[Brian Wilson]

And smoke the intake as soon as I find someone local with the right equipment to do it

 

[MichaelSE]

No sir. Any help is appreciated. One guy told me my carb float might be stuck so..... no advice is bad advice. I have tried that but, since the position of the throttle plate is not exactly linear with flowthru, it's really hard to say if that it's the issue. I guess my next step is to swap the throttle body itself with my brothers denali while I wait for justin to get back with me.

Definitely worth a try. Have you cleaned your PCV channel hoses? I sprayed carb cleaner through mine a few weeks ago and the amount of crap that came out of them was crazy.

 

[Brian Wilson]

I have not tried that. But I probably should. Although I need to do it, I doubt a slight excess in crank case pressure would do cause what I'm experiencing right now. But I will do do asap since I'm waiting to install a catch can I bought a few weeks ago. It would be a good time to do both!

 

[#1taho]

No sir. Any help is appreciated. One guy told me my carb float might be stuck so..... no advice is bad advice. I have tried that but, since the position of the throttle plate is not exactly linear with flowthru, it's really hard to say if that it's the issue. I guess my next step is to swap the throttle body itself with my brothers denali while I wait for justin to get back with me.

Carb float ?! That's worse than the advice I gave you. Mine was a stab in the dark cause you seem to have coverd everything. Don't rule out a faulty new part tho. Had a few of them in the past

 

[ISU-152]

Egr?

 

[Brian Wilson]

Thanks for the help. But which new part ....

 

[ISU-152]

You've done a ton and it sucks I know. Try cleaning your egr valve.

 

[Brian Wilson]

Adding it to the list. I should have it all done this weekend easily

 

[Brian Wilson]

Just took the plunge for the 600$ v2 from blackbear. Hopefully they can give me a tune that will solve my issue or at least point me in the right direction about the problem. Still super excited to get it.

 

[iamdub]

Try to get some details if BB sees something and you get this sorted out. I have an '08 5.3 (AFM, no VVT) that seems like it should have much more lower-RPM power than it does. It's like VTEC kicks in around 4,500 or so. Although, this is my first of this type of vehicle so it may be perfectly fine and normal.

 

[Brian Wilson]

I would be of no help. I hate everything about my car except the 6 speed and the 6.2. If they sold a base tahoe with a 6.2 6 speed package and a hitch, I would have gladly bought that instead. All those wonderful electronics are just more trouble later.

 

[Tonyrodz]

I would be of no help. I hate everything about my car except the 6 speed and the 6.2. If they sold a base tahoe with a 6.2 6 speed package and a hitch, I would have gladly bought that instead. All those wonderful electronics are just more trouble later.

Hell yeah! !

 

[Da90]

Glad I saw this! My 08 Sierra Denali has done this twice. It happened today... I have the auto cal but I'm chasing high and low codes. I found the service bulletin but haven't tracked down the problem yet.

Edit: high and low voltage codes
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[Brian Wilson]

High and low codes? Never heard of this

 

[Da90]

High and low codes? Never heard of this

http://repairdata.cnlaunch.com/pdf/2013/09/25/91ba623e-0f70-4621-9342-f4c7d469e48a.pdf

I had to edit my original post cause I left out a word.

That is what I found and my buddy at the dealer said the same thing. I'll be driving and all the electronics will shut off and come right back on. The motor has shut off once that I can positively remember. I have a code reader and it throws both the codes in the link. I have replaced the main fuse and and cleaned the easy terminals. I'm thinking next is battery and alternator cables.


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