2003 Tahoe engine cuts off

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Schebes
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Joined: Fri Aug 01, 2014 8:40 pm

2003 Tahoe engine cuts off

Unread post by Schebes » Fri Aug 01, 2014 8:55 pm

This just started , my 03 Tahoe while going down e-way started running rough then the engine quit. It would not restart right away but after sitting for 1 1/2 hrs engine restarted then did the same thing after about 2 miles. Had towed home and after sitting for several hours starts right up and running smooth. Did not take for ride but check engine light is on. Only code pulled is P0161 O2 heater circuit bank 2 sensor 2. I don't think a bad O2 sensor would cause this. Seemed like not getting enough fuel. Looking for some ideas as to where to start. I do have a remote start on the truck but again not sure if that could cause the problem. Any thoughts would be appreciated. There were no other sounds outside the rough running and loss of power. I have the 4.8L engine.

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carriedi
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Re: 2003 Tahoe engine cuts off

Unread post by carriedi » Sat Aug 02, 2014 8:12 am

I have seen it where a bad O2 sensor can cause the engine to stall but usually it is the pre-cat O2 sensor, not the post-cat. but, it is still a possibility. However, the engine would restart up right away. A fuel pump going out could cause symptoms like you experienced. there are also other things that could possibly affect the engine and cause the problems you describe.

a shop would test drive your vehicle with a scanner and watch the data stream for glitches. watching your fuel trims and O2 sensors. or current ramp your fuel pump to see if the waveform looks normal
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Schebes
Posts: 4
Joined: Fri Aug 01, 2014 8:40 pm

Re: 2003 Tahoe engine cuts off

Unread post by Schebes » Sat Aug 02, 2014 9:18 am

I took the truck for a test drive and after a couple of minutes did the same thing. I sat and waited about 15 minutes and it restarted, got it back in the drive and let it run. About 10 minutes later it shut down and would not restart. I noticed the time on the clock is wrong so I know there was a loss of electricity. Could there be something heating up and losing connection due to expansion? Just pulled one of the spark plugs and tried starting with remote, had no spark. remote cycled thru to restart and I had spark and the engine started. I believe I have an intermittent spark problem. any thoughts on what this might be would be appreciated.

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carriedi
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Re: 2003 Tahoe engine cuts off

Unread post by carriedi » Sat Aug 02, 2014 5:42 pm

if you lost the clock memory then I would start looking at your powers and grounds. Thing is that clock memory is a power all the time. Not run through the ignition switch. Make sure your battery cables are good and clean. side terminal cable ends may have build up inside the cable bolt so you should take the bolt out of the cable and clean underneath. if you were driving and lost your clock you should have noticed if other things like the radio stations were lost. (you may just have a bad clock)

when you say it won't restart you mean the starter turns the motor over it just won't start right?

there is a TSB for no start for 03 tahoe. 03-08-50-014 it can cause codes, stability message, abs light, and other symptoms. they say there is a wire harness that goes under the drivers seat that can get pinched or rubbed through.

as far as the no spark while cranking with the remote, I would prefer to have someone turn the key to verify the no spark condition. If there is no spark see if there is injector pulse. If both are not present I would look at your crank sensor. see if you are getting your 24x signal.
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Schebes
Posts: 4
Joined: Fri Aug 01, 2014 8:40 pm

Re: 2003 Tahoe engine cuts off

Unread post by Schebes » Sun Aug 03, 2014 4:42 pm

I appreciate the help. Unfortunately I am going to have to take it to the shop. Did not find and broken or loose wires, battery cables are good and clean, tried replacing the crank shaft position sensor- no help there. The truck does not start at all now so I am out of ideas. Thinking it is either the harness to the sensor or the PCM. Still possible there is a bad ground wire but I can't find it if there is. and I don't want to waste any more time and money replacing parts that are good. Engine does crank over but no spark, I checked all eight cylinders. Who knows maybe all 8 coil packs went bad at the same time.

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carriedi
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Re: 2003 Tahoe engine cuts off

Unread post by carriedi » Thu Aug 07, 2014 10:17 am

today,s vehicles are much more complicated than previous models. you need special tools and equipment to work and diagnose them. You should check out rather than replace items. Taking it to a shop to have it diagnosed is a good option if you don't have a scanner and wiring diagrams available.

You would need to see if the computer is getting a signal to fire the coils or if the computer is sending out a signal to fire the coils. The computer sends the ground signal to fire the coils. Using a test light hooked up to the coil connector (unplug coil and use test light in place of the coil) one side should be battery power and the other side a blinking ground while cranking the engine over. It would very unusual for all 6 coils to go out at the same time. More likely you either don't have the power side or the computer is not sending the ground signal. you would need to know how to go through and see where the problem is if the computer is not sending the ground to the coils.

scanners and a lab scopes are essential for diagnosing todays cars and trucks.
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Schebes
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Joined: Fri Aug 01, 2014 8:40 pm

Re: 2003 Tahoe engine cuts off

Unread post by Schebes » Thu Aug 07, 2014 5:51 pm

I appreciate it. Turned out to be a bad ground. Cleaned all the ground terminals and is running fine now.

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carriedi
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Re: 2003 Tahoe engine cuts off

Unread post by carriedi » Thu Aug 07, 2014 10:54 pm

hey, congrats on finding the problem
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