2002 GMC Envoy Rough Idle After Start

GMC ENVOY
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ARIEL
  • MEMBER
  • 2 POSTS
My 2002 GMC Envoy has 106,000 miles on it. When I turn it on (morning or after long time being off) it will idle fine and drive fine, but when I drive from parking lot and come to a stop soon at end of parking lot, it will idle very rough. This is the only time it will happen, and idles smoothly all other times. This problem has been happening for the past 10k miles

I have changed spark plugs, fuel filter, and have done a complete fuel injection cleaning, where fluid sent directly to injectors, throttle body cleaned, and treatment added to gas tank. I only use high quality gasoline, and keep maintenance regularly.

Please help with any and all suggestions

Thank you

Ariel
Apr 14, 2006 at 4:12 AM
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LOSONE
  • ✓Experienced Mechanic
  • 1,616 POSTS
Sadly you have a Vortec system. All of the injector components are buried inside the intake manifold. Sounds like either the fuel pressure regulator or one of the plastic lines leading to the injectors is bad. The unit is over $600.00 and a pain to replace. Good luck
Apr 14, 2006 at 4:18 AM
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HUNTER
  • MEMBER
  • 11 POSTS
Check you vacuum lines especially from the fuel regulator. Any leaking line could cause this. Also, check the plastic tee's to see if any are cracked.
Apr 14, 2006 at 9:39 AM
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Suggested Repair

Inspect the fuel pressure regulator, its vacuum lines, and the plastic injector lines and tees for leaks or cracks. On this Vortec setup those parts sit inside the intake and can be costly to replace.

Conversation Summary

A 2002 GMC Envoy with 106,000 miles idles roughly only after the first stop following a morning or long-sit start, then idles smoothly otherwise. Spark plugs, the fuel filter, injector cleaning, and throttle-body service did not fix it. Replies suggest a bad fuel pressure regulator or leaking vacuum and plastic injector lines or cracked tees, noting the Vortec components are buried in the intake and expensive to replace.

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