My 99 Tahoe was running great and suddenly died at a stop sign. It would not start at first. I waited 5 minutes and tried again and she started up. I put my foot on the brake and she died again. I started her up reved her a bit, put my foot on the brake to to engage her and the engine died. I start it up, open the driver's side door, and the engine died. I started it again and turned on the hazard lights and it died. Help!!!! What coiuld be the issue here??? Looking for any suggestions on where to check. My husband is at a loss and she is being towed home as we speak. (We did check for diagnostic codes but there were none) Any help would be greatly appreciated!!!! Thank you!

 

Any smoke when starting?
Runs if keep giving fuel?
I'd start with a fuel pressure check and looking for a vacuum leak.

 

There was no smoke when starting it up at all. When I reved it up or left it idle, it ran as long as I did not touch anything else. As soon as I touched anything, it would die quicky!!!!

 

Kinda sounds like some weird electrical short. My 68 El Camino had a shorted hi beam switch - it would run on hi beams but when switched to low it would turn off like using the key.

 

Update.....Just got the my Tahoe home after sitting all night in a hospital parking lot. The rollback driver said that when he got in it, he started it up and it started fine. He said he drove it right up onto the roll back and had no issues at all. When he got here, he got in it again, started it up and backed it right off the roll back, It did not die at all,. My husband got in it, started it, and turned it around in our driveway so that he would be able to get underneath it if need be. All seems to be running fine. What is the deal here??? What gives????? Suggestions???? (I know I need an O2 sensor, I have it but have not replaced it yet...but would it do all of this?)

 

Can you give the history of the vehicle, have you owned it since new, has the fuel pump been replaced? Could be an intermittent fuel pump issue, and as stated check fuel pressure. O2 sensor won't cause this.

 

When it dies, does it quickly cut off like turning off the key, or does it sputter out more slowly?

 

I have owned the vehicle since 2005 but it was in the family beforehand. This Tahoe had a brand new crate 5.7 L motor put in it at the chevy dealership 4 years ago. Yes, the fuel pump was replaced about 5 or 6 years ago. All was running fine and then when we came to a stop sign, the tahoe just went kaput. When the engine would die yesterday, it would just stop like the key would turn off. Everything would go off. It would restart with the turn of the key and run, but when you put your foot on the brake to shift into any gear, or turn on the hazard lights, turn on just the heat, or even just open the car door, the engine would die. So when the roll back driver said that he started the Tahoe and put it in gear and drove it right up onto the rollback, I was shocked!!!! I am just so confused here!!!

 

These things never happen when you have them to a mechanic. What I read in your post everything points to ignition switch.

 

From what you describe it sounds like a complete loss of electrical power to the engine.Since it has no problem cranking the engine over , I would be inclined to agree there is a good possibility the ign switch may have a problem. If a test lite or voltmeter were connected to any source of key on power and it dropped off when any kind of electrical load was placed on that part of the system, like opening a door or stepping on the brake pedal you would have a visual indication of what is happening.