Lurching and Hiccups

[tiktok4321]

This issue has been plaguing me for several years. As I would approach a light and apply the brakes, the truck would lurch as it went into Auto Stop, bang a bit then act like nothing happened. Then, upon accelerating out of Auto Stop, it would bang a couple times. If I just let off the accelerator, let it do it's angry thing and finish, I could continue without any issue. This would throw a P code or three. I found that driving in M4 would completely eliminate the problem. The problem ALSO went away for quite some time after I replaced the Hybrid battery.

This weekend, I decided to replace the throttle body & sensor. I have NOT taken the truck to get the new throttle body programmed. I read that it would eventually self adjust. First couple hours it didn't ever go into Auto Stop. After about 200 miles, including a couple hours on the interstate, it seems to be cooperating nicer. It will go into Auto Stop, but not near as often as it used to. I'm now averaging about 21 MPG, and the lurching in "D" has reduced by about 95%, but it hasn't been eliminated.

Any further suggestions? Am I doomed to taking it to GM for a throttle body calibration?

 

[Doubeleive]

clean or replace the maf and new air filter as well, that "should" help.

 

[swathdiver]

@BG1988

 

[tiktok4321]

Here's another question.... The fresh air intake has this bulbous "can" on top of it that looks like a paint ball reservoir. It had previously broken off and caulked back on. It broke again. I glued it on with super glue and it's on tight. Could still be leaking, though. I can caulk it up again, but I'd rather replace it. Only problem is it seems like NO ONE sells it any more! I can only seem to replace the intake pipe with after market K&N filter to throttle body kits in the $400 range. don't want to spend that for a piece of plastic.

 

[Doubeleive]

Here's another question.... The fresh air intake has this bulbous "can" on top of it that looks like a paint ball reservoir. It had previously broken off and caulked back on. It broke again. I glued it on with super glue and it's on tight. Could still be leaking, though. I can caulk it up again, but I'd rather replace it. Only problem is it seems like NO ONE sells it any more! I can only seem to replace the intake pipe with after market K&N filter to throttle body kits in the $400 range. don't want to spend that for a piece of plastic.

yes that would allow unmetered air to enter the system and cause problems like you are experiencing, not sure if the hybrid intake is any different than a regular 5.3 but a junkyard probably has one.

 

[BG1988]

This issue has been plaguing me for several years. As I would approach a light and apply the brakes, the truck would lurch as it went into Auto Stop, bang a bit then act like nothing happened. Then, upon accelerating out of Auto Stop, it would bang a couple times. If I just let off the accelerator, let it do it's angry thing and finish, I could continue without any issue. This would throw a P code or three. I found that driving in M4 would completely eliminate the problem. The problem ALSO went away for quite some time after I replaced the Hybrid battery.

This weekend, I decided to replace the throttle body & sensor. I have NOT taken the truck to get the new throttle body programmed. I read that it would eventually self adjust. First couple hours it didn't ever go into Auto Stop. After about 200 miles, including a couple hours on the interstate, it seems to be cooperating nicer. It will go into Auto Stop, but not near as often as it used to. I'm now averaging about 21 MPG, and the lurching in "D" has reduced by about 95%, but it hasn't been eliminated.

check the battery cables(in regards to the autostop) most likely they're loose and/or the posts are crushed the TB does not need to be programmed as it's perfect from the factory... when keyed off it should be at 12.8-12.9v if it's at 12.2 - 12.5 then loose and/or the posts are crushed...this will keep the engine running longer and to fail to enter autostop event, while getting worse MPG..

the autostop relies on the 12v+ battery more then many people want us to believe(checked with the mutimeter you can see a dip when the engine is restarted (like normal car) this is why I suspect the 12volt rail Capacitors inside the inverter module are worn out.) as were about 14-15 year in on these rigs at lest pulling 100-120 amps upon resume...(i.e ignition system 20amps ,AUX pump is 50amps running and what ever else is running.....)



i would look into getting one of these https://www.ebay.com/itm/164960821660


yeah 180 but still cheaper then getting a replacement inverter module



acting like a misfire ?? or shutter?


i found a hidden TSB apparently there was a design issue(passage way was too small and caused pressure issues) inside of the transmission on 2008 model year that causes the shutter or misfire feel .....(i'll have to re-find it though as i found it by accident while looking up other stuff )

too much fluctuating voltages might cause a drop in output voltage to the transmission pump since it uses a 12v+ DC to 3 phase inverter for the Aux transmission pump... a small drop in the AUX pressure can effect first, second gears well as Autostop(fail to enter autostop)

 

[tiktok4321]

I've heard the 12v theory a lot. I've replaced the cable terminals and the batteries themselves. I'll check the voltage drops.

 

[BG1988]

I've heard the 12v theory a lot. I've replaced the cable terminals and the batteries themselves. I'll check the voltage drops.

the issue is the terminals connectors bad design i had to put a shim on my neg terminal(as well as the positive cable) because of issues it charges to 12.8v now

 

[tiktok4321]

OK - replaced air sensor and throttle body/sensor. Not as bad, but still lurches. Battery at rest is 12.3v. When on, it's 14-15v.

 

[dnt1010]

I just figured that that all the two modes have an occasional jump lurch thing? Mine is just so rare that I have never been able to tie it directly to a certain condition of going into or out of autostop etc. It just feels like someone hit your back bumper and pushed you forward when it happens LOL. Maybe we can start a poll of how many two mode owners have the jump lurch thing and how often. Put me in for "yes have it" and approx every 6 weeks Hahah