Engine won't stay running, stalls while driving?

2003 CHEVROLET SILVERADO
99,521 MILES • V8 • 4WD • AUTOMATIC
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JDL
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Have a helper crank it, while you check for spark at the spark plugs, when problem is ongoing. If you have spark everywhere, use a gage and check fuel pressure. Some of the national brand autostores used to loan out a fuel pressure gage.

To check for spark, where applicable, take a spark plug wire loose, use a spark tester in bott. Ground/touch metal part of tester to metal part of engine. Engine cranking, watch for spark.
Sep 3, 2020 at 11:55 AM (Merged)
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HOTROD46703
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When running and rpm's at 1000, but when you put it in drives fine and when you turn right it shuts off. Can any one help? Then the rpm's go to 500 after restarts.
Sep 3, 2020 at 11:55 AM (Merged)
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F4I_GUY
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First thing you should do is scan for faults. There should be faults stored if the vehicle is stalling. If not I would suspect a possible vacuum leak or idle air control valve since the idle is changing from 500-1000rpm
Sep 3, 2020 at 11:55 AM (Merged)
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LUKESANDIEFER
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My truck (1500 model) idles and revs up fine, but when I let off the throttle it bogs and sometimes shuts off. When I put it into gear, the rpm’s drop severely and it stalls out sometimes. The truck has a more aggressive cam installed, along with headers, a cold air intake, a flashed computer, 4:56 gears, and is seven lifters, push-rods, rockers, and all that good stuff. I was told the transmission has a shift kit also. I have been told that it could be the IAC valve, a dirty throttle body/throttle plate, or maybe even a dirty MAF sensor. Let me know please.
Sep 3, 2020 at 11:56 AM (Merged)
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JACOBANDNICKOLAS
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Any of the items you listed could cause the aforementioned problem. However, you should still be able to scan the computer to determine if there is a trouble code that would point you in the right direction. Have you done that? Also, I would recommend checking for engine vacuum leaks.

Please keep in mind, considering the amount of work that has been done to the engine leaves many possible things to consider. However, considering the IAC does maintain engine idle speed because the throttle plate fully closes when you let off the gas, that would be the first thing I would suspect. Also, the idea of a vacuum leak could also be an issue.
Sep 3, 2020 at 11:56 AM (Merged)
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LUKESANDIEFER
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Thank you, I will scan the truck this coming week.
Sep 3, 2020 at 11:56 AM (Merged)
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ADRCHER
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Did you find a solution for this? Have silar mods and similar problem!
Sep 3, 2020 at 11:56 AM (Merged)
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JONNYB1963
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Hello! Thanks stopping in!

For better service here can I ask you start a new question. Just click on this link: https://www.2carpros.com/questions/new
Then tell us what vehicle you have and then describe your problem.

It’s just that this is a old post this will get you better service!

Jon
Sep 3, 2020 at 11:56 AM (Merged)
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