09 Tahoe Hybrid Misfire Rough Ride Help Needed!!

[Jerry Orldrive]

Hey Guys! I posted this to green hybrid with no success so was hoping someone could help me here. Read below the HELP WILL BE RETURNED!

My 09 Tahoe hybrid has been having stalling, lurching and cylinder 7 misfires recently.


Rides very rough especially when idle or in reverse. Seems to be when the two mode is trying to shut down four cylinders or switching to hybrid mode. Also there is oil leaking out like crazy from underneath around the aux trans pump. the fuel pressure will go up and down while driving (I occasionally smell burning oil not gas.

the aux pump it seems to be leaking engine oil and it smells like engine oil and my mechanic said it was indeed. Auto shops flat out tell me to go to the dealers except my mechanic friend who is literally doing the research I am.

I can’t accept taking it to a dealer who will just redo all the **** I did above and charge me 10K. I am an orthopedic surgeon and will repay the best help with free phone injury consultation for friends or family!!

(I am a weekend warrior but a NOOB to hybrids). All the below was done with a very competent mechanic...the THIRD ONE stumped by the problem. II own several cars and rent them on TURO so I am DETERMINED to get to the bottom of this.



Codes shown:


P0300


(P0307, P0430 & P0455 but not anymore all these went away )


says “service hybrid system” on dash.



Things we’ve tried:


-We checked the fuel injectors and they are in good shape.


-we did engine oil and trans oil changes


-we shifted the car into M and the same exact shuttering and sounds occurred when the hood was popped in auto stop.

No

. I placed the vehicle in park and attached two videos of the symptoms.


-cleaned out mass airflow sensor and replaced


-air filter change


-new 12V battery


-Changed all the spark plugs (yup went in behind the passenger wheel under the splash guard)


-changed the coils.


-replaced throttle position sensor and throttle and cleaned with electric cleaner


-used cataclean and laquer thinner on the cat through gas tank (like Scotty said) and that cleared the P0455 and P0430


-drove around with mechanic who had attached his 7k obd reader. He only saw misfires and said it’s communication between the hybrid trans and engine and its getting confused but he isn’t 100%.



Is it a matter of cleaning the corrosion on the hybrid battery?



is it the aux trans pump?



Please help!!!

 

[Doubeleive]

@BG1988 MIGHT have some insight, have an open mind, lol

 

[Fless]

Isn't cylinder 7 one of the AFM cylinders? If so, and it seems to happen when switching modes, you may want to look into a lifter issue.

 

[Jerry Orldrive]

@BG1988 MIGHT have some insight, have an open mind, lol

I’m all ears!

 

[BG1988]

aux are weak on the 08/09 and have a new revised update to the pump on the 2010+



so you will have autostop lag or stall out...


THIS is very dangerous I all ready have stall out multiple times luckily it happened while making turns on a protected LEFT turn(could be a loose wire?)

Now that i think about it. It happened mostly while making a left turn (did it twice on a right turn)


Some people have reported disconnecting and cleaning the connectors for the AUX pump and that correct the Autostop LAG




sometimes mine shutters at 10mph if I shift from reverse to drive and go too quick but i do suspect the big battery is causing it... since there is E-assist in m4

i had just been using m4 most of the time lately so i don't have to deal with the stall outs which have to do with the Aux pump(auto resume while in motion ) i would find out the Hybrid code so i could look it up....


misfires can be with the spark plugs or cables...

check and make sure the baro and MAP sensor is reading correctly there is 2 sensors

they should match ACC key on (don't start engine)

but the shuttering should go away once the misfire is gone..per my experience .


also has the battery been tested? if there is an issue with the 12v+


(this would be the first to check) most people that have issues it mostly stems from a bad battery (it typically ignored tell it has less then 100 cranking amps of power, because the BIG battery starts the car)


I had some crazy stuff happen with a faulty 12v+...

such as the brakes locking up while going 55mph!
YEAH 100% lockup everything went off inside...



also make sure the leads to the battery are sung and pushed all the way down the battery post( it should not be loose or able to move them.)

 

[Jerry Orldrive]

aux are weak on the 08/09 and have a new revised update to the pump on the 2010+



so you will have autostop lag or stall out...


THIS is very dangerous I all ready have stall out multiple times luckily it happened while making turns on a protected LEFT turn(could be a loose wire?)

Now that i think about it. It happened mostly while making a left turn (did it twice on a right turn)


Some people have reported disconnecting and cleaning the connectors for the AUX pump and that correct the Autostop LAG




sometimes mine shutters at 10mph if I shift from reverse to drive and go too quick but i do suspect the big battery is causing it... since there is E-assist in m4

I agree it is the big one for sure.

i had just been using m4 most of the time lately so i don't have to deal with the stall outs which have to do with the Aux pump(auto resume while in motion ) i would find out the Hybrid code so i could look it up....

I have tried M4 and it ride the very same

misfires can be with the spark plugs or cables...

take a look at my original post. I have done it all.

check and make sure the baro and MAP sensor is reading correctly there is 2 sensors

I do not know what this means but will find out.

but the shuttering should go away once the misfire is gone....

I believe as stated above the misfire is due to the system not registering to the engine from the drive shaft (which is directly dependent on the battery) thus it’s going into two mode and confused to shut off the four cylinders.


also has the battery been tested? if there is an issue with the 12v+

brand new batter and corosion and cables pristine. Throttle body and sensor changed as well.

(this would be the first to check) most people that have issues it mostly stems from a bad battery (it typically ignored because the BIG battery starts the car)


I had some crazy stuff happen with a faulty 12v+...


also make sure the leads to the battery are sung and pushed all the way down the battery post( it should not be loose or able to move them.)

yes 100% did this as well


Really read all I went over it all.
Does this mean replacing the six trans pump will help?

or should I buy a refurbished hybri battery?

 

[Jerry Orldrive]

Isn't cylinder 7 one of the AFM cylinders? If so, and it seems to happen when switching modes, you may want to look into a lifter issue.

It’s misfiring on all cylinders not just seven. I believe it’s when it goes into two mode. See above I’m very descriptive.

 

[BG1988]

yes 100% did this as well


Really read all I went over it all.
Does this mean replacing the six trans pump will help?

or should I buy a refurbished hybri battery?

I would deal with the engine issue first.. the AUX pump only runs when it's in autostop.. it's to keep the transmission pressure and oil circulation


the shuttering will correct it self when you fix the misfire...

has the fuel pressure been tested??
have the plugs been inspected? when mine was misfiring the electrode had the ceramic all blown apart

I only got 99,950 miles out of that 100,000 rated plug..


tell us the hybrid code (sometimes you can get the code from freeze frame data) if his 7,000$ scanner can't read them

 

[Jerry Orldrive]

I would deal with the engine issue first.. the AUX pump only runs when it's in autostop.. it's to keep the transmission pressure and oil circulation


the shuttering will correct it self when you fix the misfire...

has the fuel pressure been tested??
have the plugs been inspected? when mine was misfiring the electrode had the ceramic all blown apart

I only got 99,950 miles out of that 100,000 rated plug..


tell us the hybrid code (sometimes you can get the code from freeze frame data) if his 7,000$ scanner can't read them

I appreciate you very much!
I’m just so frustrated.
It isn’t throwing any codes on my OBD for the hybrid but the dash says service hybrid system I will see if I can from the freeze frame thank you.

I changed all the plugs myself and the coils but the fuel pressure I am not sure about but it was throwing evap leak and cat converter codes prior to this.

If you had to guess what would be the two most likely issues? I can email you videos of it ect if that helps?

 

[BG1988]

I appreciate you very much!
I’m just so frustrated.
It isn’t throwing any codes on my OBD for the hybrid but the dash says service hybrid system I will see if I can from the freeze frame thank you.

I changed all the plugs myself and the coils but the fuel pressure I am not sure about but it was throwing evap leak and cat converter codes prior to this.

If you had to guess what would be the two most likely issues? I can email you videos of it ect if that helps?

just get the code from it i'll look it up