Rough idle after running for a couple minutes?

1994 CHEVROLET SILVERADO
174,000 MILES • 4.3L • V6 • 4WD • MANUAL
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ANDREW HAAS
  • MEMBER
  • 1 POST
I bought the truck listed above 1500 w/t about a month ago and it ran great for the first couple of weeks. It recently started to run rough about once a week. I did spark plugs, wires, distributor cap and rotor. That seemed to fix up until about a week ago it started to randomly run rough until you drive it for a couple miles. After that it will idle fine. I drive about 40-50 miles a day. It starts fine and drives fine, it’s just the idle is very rough and it will seem to surge in power and try to shut off. I am at my wits end and if anybody can help, I would appreciate it.
Mar 5, 2023 at 7:52 PM
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STRAILER
  • Experienced Mechanic
  • 55,256 POSTS
I have seen the EGR valve on these truck stick open sometime which will cause the rough idle condition you have described. Here is a guide that can help you and I have included a video on how to test the EGR valve with instructions below on how to replace it.

https://youtu.be/DqUCbbKdWf4

and

https://www.2carpros.com/articles/troubleshooting-rough-idle-in-your-cars-engine-7-common-causes-and-how

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem.

Mar 6, 2023 at 3:54 AM
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