1990 Other GMC Models Failed California smog

1990 GMC
246,000 MILES • V8 • 4WD • AUTOMATIC
Avatar
LINVDAN
  • MEMBER
  • 1 POST
I just failed CA smog, my HC levels are as such
Idle- RPM- 1062, HC measures 173
2500 RPM- HC measures 400

What should I do to correct this? Truck seems to run fine.
Thanks
Aug 19, 2008 at 6:51 PM
Advertisement
Avatar
2CARPRO JACK
  • ✓ASE Certified Mechanic
  • 11,533 POSTS
  • ASE Certified Mechanic
At that mileage, it could very well be the cat converter is all used up. They are a reactive material and will only last so long
Aug 22, 2008 at 12:19 PM
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.