Two Failed Cats - S-10 4.3L @ ~65K Miles?

Greg · December 14, 2004

My daughter is using my son's truck while he's in Iraq. She started having problems with lack of power and the check engine light came on. Since she lives in another city, a buddy of mine that lives there directed her to a reputable local garage. The codes said the problem was a bad MAFS, but further research showed it was clogged cats. Is this a common problem with the 4.3? She said she tries to run Shell in the truck because people in town report problems with other brands of gas sold there. Thoughts?

GM-Tech · December 14, 2004

Biggest cause of failed cats is a misfire. BTW, cats are covered for 8/80, so I hope you didn't pay for the repair.

Greg · December 15, 2004

Thanks for the info. I called down there and told them to pay the garage for the diagnosis and get the truck to the Chevy dealer.

JimsZR2 · December 15, 2004

Misfire can do it... But don't rule out a faulty O2 Sensor. That could be making the engine run a little rich. Then all that raw fuel dumps into the cat and fries it.

Greg · December 24, 2004

Thanks again to GM-Tech. We were looking at a $400 - $800 bill from the garage to replace the cats. She paid the garage $60 for the diagnosis, they pulled the O2 sensors from the manifolds so she could drive the truck (noisily) to the Chevy dealer, and everything was covered under warranty.