Losing engine power with no warning


Asked by Aug 10, 2014 at 11:38 PM about the 2007 GMC Yukon XL Denali 4WD

Question type: Maintenance & Repair

I recently took my Yukon (140,000miles) up to a local mountain(4000ft elevation) , it
drove up the curvy steep road fine. Engine ran a little warm, a smidgen above center, but
no problem till we approached a stop sign. When the break pedal was touched the
engine lost power-- with no warning lights or check engine light. The dash lights,
overhead lights, radio etc stayed on, then the engine temp gauge read close to red--still
no warnings, or check engine light. The car wouldn't restart. After a few minutes the
battery was dead too. 3 different people tried to jump us with no luck, finally two hours
later we successfully jumped it---drove fine down the mountain (no check engine light
still). Took it to a dealer, they didn't find any codes. Ended up replacing the oil pressure
sensor, thermostat, flushed rad & new coolant. We test drove it back up the mountain,
and the damn thing did it again. I'm at a loss, it seems as if it's not throwing any codes
the dealer won't fix anything. I'm worried about the potential danger this could be, a car
just losing all power! any ideas what's going on?

8 Answers


Hi Jim, thanks for your response. Apparently, this Yukon is suppose to go into the "low power mode" where it shuts off the a/c, drops you down to <30mph or so when the engine overheats! But it appears there is a miscommunication occurring = no check engine light, no protective mode etc.. The coolant temp sensor seems like a good place to start! To my limited knowledge, it didn't appear to be overheating (no bubbling, steaming, hot smell etc) and the gauge read pretty normal till the engine cut out! But I will check on the sensor, thanks!

4 people found this helpful.

My 07 Yukon denali shut down on me it seems like it's fighting for gas but I had gas in the tank is change the fuel pump but getting the same problem when I drive the truck regular I don't get that problem but when I drive it hard it start shaking and shut down and when the engine cool down it would start back can someone tell me what is that problem please

7 people found this helpful.

did you ever find the problem my 2002 has started doing the exact same thing

3 people found this helpful.

Hi all. So I was having the same issue where my 2012 GMC Yukon XL Denali would randomly go into limp mode with no rhyme or reason. Every time it did, we would bring it to the local Chevy dealer, but they were never able to find a problem with it. It had happened again one time & caused my wife to get into an accident. We immediately brought the car back to the dealership and once again, they couldn't find anything wrong with the vehicle. After the repairs were done from the accident, we got the vehicle back and low and behold, it happened again. Long story short, this time we brought it back to the dealer, and the service manager told me that when we get there, don't turn the truck off and come and get him. Well, this made a difference. Apparently, every time we brought the truck there, we would park it and turn it off (as reasonably expected) which would in turn reset the computer the next time it was started up. Since we never turned it off, he hooked up the code computer and was able to get 2 different codes from the vehicle. One of them showing that there was an issue with the transponder in the key which was screwing with the receiver in the ignition sporatically, and the vehicle would think that it was being stolen and go into limp mode. The service manager had a new key made up, and we haven't had an issue with the electrical system since. Hope this sheds some light and helps.

1 people found this helpful.

My 08 Yukon Denali is having the same problem. $800 in mechanical bills and it’s still doing the same thing. Shannon did you ever figure out what was causing??

1 people found this helpful.

I think I found the problem

1 people found this helpful.

2005 GMC yukon xl ... losing power too. When u first start it .. it's good. When you press down on the accelerator pedal it doesn't work... it just gets slower and slower. I really need help. Thanks 6.25.19


Try unplugging it from your gas pedal inside the truck and plug it back in

1 people found this helpful.

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