Will not stay running?

2002 CHEVROLET SILVERADO
250,000 MILES • 5.4L • V8 • 4WD • AUTOMATIC
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MYKKAWOLFE
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It’ll turn over and start but then shuts off. then I’ll try to turn it over again and it doesn’t start.
Aug 11, 2021 at 11:42 AM
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STEVE W.
  • Experienced Mechanic
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That description sounds like a fuel pump issue. Try this test and reply back with what you find. Turn the key on, not start, wait 5 seconds and turn it off, repeat this about 3 times and try to start it. Does it start and run or does it start run about 3-4 seconds and then shut back off?
Next look at this guide on testing fuel pressure. The pumps and wiring on that vintage GM are prone to problems. The most common is the pump failing, closely followed by the wiring to it.
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
Aug 11, 2021 at 12:47 PM
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SQM
  • Experienced Mechanic
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Hello,

So it will start up and immediately stall?
Is there a check engine light?
Trouble codes can help point us to the right direction.
There could be a number things that could trigger this issue.
An engine will need spark, fuel and compression to start and stay running.

You could have a faulty crank sensor.
It can also be that the fuel pressure drops due to a bad regulator and the engine stalls. Could even be compression issue.

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works
https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please if you would let me know little more details of what the vehicle is doing.

Thank you.
Aug 11, 2021 at 12:49 PM
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MYKKAWOLFE
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Yes, it’ll start for 2 seconds then stops and whenever I try to push on the gas pedal it doesn’t do anything.
Aug 11, 2021 at 3:21 PM
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SQM
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Check to see if you are getting fuel pressure. It sounds like either you are losing fuel or some type of sensor issue, which stalls the engine.
Also is the check engine light on?
Aug 11, 2021 at 3:25 PM
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STEVE W.
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What does the security light do when you try to start it? Starts runs 2-3 seconds and stalls is also an indication that the security system has tripped and it is shutting off the engine, would also explain the lack of throttle response. Do you have a second key you can try?
Aug 11, 2021 at 3:31 PM
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MYKKAWOLFE
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Yes, I’m getting fuel pressure and I’m not sure if it’s on I can’t get the truck to stay running long enough for the dash lights to come on.
Aug 11, 2021 at 3:32 PM
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MYKKAWOLFE
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No, I have one key but funny thing is whenever it’s running I can remove the key and it still runs.
Aug 11, 2021 at 3:33 PM
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STEVE W.
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Okay, put the key in and just turn the key on not to start. What lights on the dash come on and go off? The security light should come on and go off if it is reading the key properly. If it comes on and stays on, or flashes you have a security issue.
Aug 11, 2021 at 3:41 PM
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MYKKAWOLFE
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It flashes.
Aug 11, 2021 at 3:42 PM
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STEVE W.
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Okay, then the issue isn't directly fuel related it is that the security system has detected a problem and is shutting off the fuel system as it thinks the truck is stolen. With a flashing security light it means the key is not being detected properly, in the case of GM vehicles that is usually a fault in the sensor that is part of the PassLock system. The sensor is built into the housing that the ignition cylinder is in. To replace it you need to take the steering column apart to get to the housing and the bolts that retain it. Then replace the housing and do a 30 minute relearn process to get the security system to turn off. Replacing the housing is a bit different depending on the actual column in your truck, if it is a tilt column and if it's column or floor shift.

GM 30 Minute Learn Procedure
Turn "on" the ignition
Attempt to start the engine, then release the key to "on".
After approximately 10 minutes the telltale will turn "off".
Turn "off" the ignition, and wait 5 seconds.
Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes.
Important; the vehicle learns the PASSLOCK Sensor Data Code and/or password on the next ignition switch transition from "off" to "crank". You must turn the ignition "off" before attempting to start the vehicle.
Start the engine.

Before I replaced the housing though I would get a dealer level scan tool and use it to check the security system to see if it shows anything else wrong first as it could be an issue in the body control module or the wiring as much as the sensor itself failing.
Aug 11, 2021 at 5:37 PM
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AKROXHOUND
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If the key is significantly worn down through regular use, it could trick the PassLock system into thinking you are trying to steal the vehicle with something other than the actual key. I had that problem and took my registration to the local Chevy Dealership and had them give me the original Manufacturer keycode so a locksmith could make me a couple "like new" keys for it.
Jul 8, 2026 at 1:50 PM
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STRAILER
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Yep, well put, that is a confirmed fix there.
Jul 10, 2026 at 1:15 PM
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STEVE W.
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Not sure how that would work on an 02, they only use the PassLock sensor in the column to read a magnet attached to the key cylinder. As long as the cylinder can rotate into position it will trigger the hall effect and send the signal to the security system. The only things a worn key would do is make it harder to turn or remove the key. The earlier PassKey systems though could have issues with a worn key. The wear can make the key resistor pellet read incorrectly and trip the system.
Jul 10, 2026 at 5:04 PM
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STRAILER
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Good point Steve W.
Jul 10, 2026 at 5:53 PM
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