Engine idle

GMC C2500
Avatar
TOMHEP
  • MEMBER
  • 1 POST
I have a 1990 GMC 2500 Sierra with automatic transmission and 350 engine or 5.7 with 50,000 miles. I just replaced the engine and when I started it it will not idle but runs at about 4000 RPM's. What wrong?
Nov 17, 2007 at 5:46 PM
Advertisement
Avatar
RASMATAZ
  • ✓ASE Certified Mechanic
  • 75,992 POSTS
  • ASE Certified Mechanic
Check the idle air control valve and throttle position sensor
Nov 18, 2007 at 7:41 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.