Saying Hello, and a Few Questions

mxzeatr · December 13, 2006

First off, I just started looking on this site tonight! A lot of great info on here...I just bought my 1999 Chevy Extended Cab Short Box 4x4 about 2 months ago. I got it from an older fellow, who never really drove it hard...That I know of...The truck has 138k on it, I just couldn't pass up the deal. The truck runs and drives perfect, but now it has the check engine light on...The o2 sensor SES code came on a few days ago, so I replaced both sensors in front of the cats...Only one was bad...But I figured I would do both...So its been that long, and now its on again, saying 'catalyst efficency below threshold bank 2' So...I called my friend who is a mechanic, he said that I should replace the other o2's. So I just did that a few minutes ago, but have yet to have the light/codes cleared. I will be doing that tomorrow...Could it really be the cat bad? I guess I didn't know those went bad? I did some research about exhaust leaks, coloration of the cats, etc...All looks well, and I couldn't find any leaks...Thanks in advance!

ken1mod · December 13, 2006

It could be the cats but you are doing the repair correctly by doing the cheap stuff first.

Before you have the ses cleared, drive the truck on the freeway for at least 30 minutes or so, this action can help the cats regain efficiency if this type of driving is rare.

Ken

mxzeatr · December 13, 2006

Ok, I will do that! Thanks for the reply! Anyone else???

pm26 · December 13, 2006

Get several bottles of Chevron Techron from Walmart (about $ 7/botttle). Mix one bottle with about 8 gallons of gas in your tank and drive until almost empty. Repeat the same with the other bottle.

I would also try to use brand name gas and maybe a few tankfulls of 93 octane to see if the things improve.

Also, check the EGR valve for proper operation.

mxzeatr · December 13, 2006

Ok, I have some lucaus (SP) fuel stuff in it right now with premium fuel, wow that gets expensive! I always have used speedway gas or BP, not many other stations around here that are easy to get to...I'll start trying some stuff..I don't want to replace a cat or two! Thanks for the input!

mxzeatr · December 13, 2006

Anyone else? How would I go about checking the EGR for proper operation? I have a full tank of gas right now...But will be driving it home from school tommorrow...About 230 miles all freeway...Should I go have the SES codes cleared or just leave it on? Thanks again!