idle speed on my 1996 GMC SIERRA pickup is very high , what can cause this?

1996 GMC SIERRA
100,000 MILES
Avatar
HIVES
  • MEMBER
  • 1 POST
Its a 5.7 engine and the idle speed is very high always and theres nothing sticking that I can see.
Nov 17, 2011 at 12:08 AM
Advertisement
Avatar
ASEMASTER6371
  • ✓ASE Certified Mechanic
  • 52,796 POSTS
  • ASE Certified Mechanic
check the throttle body gasket. common failure that causes a high idle condition. Also check the EGR valve here is a video to show you how.

https://youtu.be/DqUCbbKdWf4

Check out the diagrams (Below). Please let us know what you find.

Cheers, Roy
Image (Click to enlarge)
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Nov 17, 2011 at 12:13 AM
Avatar
RASMATAZ
  • ✓ASE Certified Mechanic
  • 75,992 POSTS
  • ASE Certified Mechanic
I had this problem It was the EGR valve.
Nov 17, 2011 at 12:14 AM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.