2012 Denali with 6.2 engine shutting off while driving. Random

[testdepth]

Two weeks ago my wife was driving this Yukon down the road at 45mph and the engine shutoff. She coasted to the side of the road. She shifted it to park and it immediately started back up and no problems the rest of the day. Earlier this week she got in the car in the morning and when she stopped at the corner the engine shutoff again. Same thing as before, she shifted to park and immediately restarted with no problem the rest of the day. This day she then drove 3 hours round trip with no issue. Since this last time it happened the Yukon has started and ran with no problem. It was just the two times that it stalled.

No check engine light
No codes thrown for anything
No rough idle

Any ideas or where to start to narrow down what is happening?

 

[mikez71]

If electrical isn't bugging out, I would lean towards fuel pump or fuel pump control module maybe?

 

[testdepth]

If electrical isn't bugging out, I would lean towards fuel pump or fuel pump control module maybe?

No issues with electrical at anytime. I'm leaning towards a fuel pump assembly getting ready to fail but no hard starts or stumbling of engine. It just shutoff like someone flipped a switch.

 

[Geotrash]

Two weeks ago my wife was driving this Yukon down the road at 45mph and the engine shutoff. She coasted to the side of the road. She shifted it to park and it immediately started back up and no problems the rest of the day. Earlier this week she got in the car in the morning and when she stopped at the corner the engine shutoff again. Same thing as before, she shifted to park and immediately restarted with no problem the rest of the day. This day she then drove 3 hours round trip with no issue. Since this last time it happened the Yukon has started and ran with no problem. It was just the two times that it stalled.

No check engine light
No codes thrown for anything
No rough idle

Any ideas or where to start to narrow down what is happening?

Check and reseat the battery terminal connections

 

[swathdiver]

Two weeks ago my wife was driving this Yukon down the road at 45mph and the engine shutoff. She coasted to the side of the road. She shifted it to park and it immediately started back up and no problems the rest of the day. Earlier this week she got in the car in the morning and when she stopped at the corner the engine shutoff again. Same thing as before, she shifted to park and immediately restarted with no problem the rest of the day. This day she then drove 3 hours round trip with no issue. Since this last time it happened the Yukon has started and ran with no problem. It was just the two times that it stalled.

No check engine light
No codes thrown for anything
No rough idle

Any ideas or where to start to narrow down what is happening?

Order up a little ODBII adapter for your phone and download an app like Torque Pro for it. Get it set up and watch the fuel pressure if you can replicate conditions.

It ought to be 43.5 psi once warmed up and running. Idle and at speed. If you have access to a Tech-2 you can view failure records and the fuel pump trims for starters.

 

[testdepth]

Check and reseat the battery terminal connections

Did this and thanks

 

[testdepth]

Order up a little ODBII adapter for your phone and download an app like Torque Pro for it. Get it set up and watch the fuel pressure if you can replicate conditions.

It ought to be 43.5 psi once warmed up and running. Idle and at speed. If you have access to a Tech-2 you can view failure records and the fuel pump trims for starters.

I have a rather expensive OBD reader that can view everything you mentioned. I'll report back what I find and thanks

 

[testdepth]

2012 Yukon Denali XL with 6.2L and 6L80E at 172000 miles.The truck sat all night and today until 5pm when we got in it to drive up the road. Went two blocks at 15mph engine temp about 180. Foot on gas and in drive the engine starts surging and the RPMs run up to about 1500 and down to below 500 and back up. As I cruise to a stop at the light and still in drive I watch the RPM gauge drop to zero and the engine dies. I shifted to park and restarted the engine no problem. We kept driving and no more problems after engine was at normal 210F temp. No codes and no check engine light.Definitely happens when the engine is cold. After the engine is at normal temp 210F I have no issues. Have had this problem for a year.What would cause this to happen when the engine is cold?

 

[Fless]

Is this the same issue and vehicle as in your other thread?

2012 6.2L Yukon Denali XL 172000 miles? Need help and cannot figure this very random problem out.

Truck sits all night and get in to go to the store in the morning. Drive about two miles from home and engine is not fully at 210F yet with gas tank full. Stop at stop sign and turn left. Slowly accelerate but truck starts acting like it will shut off. Sort of like running out of gas as RPMs...

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