1998 Chevy Tahoe Need HELP getting past emissions

Tiny
TONYJILL
  • MEMBER
  • 1998 CHEVROLET TAHOE
  • V8
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
The check engine light is currently lit making it impossible to pass emissions (automatic fail.) We have had the diagnostic codes run and had the car inspected by a local repair shop. We were told that 2 CO2 sensors (both passengers) needed replaced and that cylinder 5 was misfiring. We performed a major tune-up to try and fix the issue with cylindar 5. We also replaced both CO2 sensors. The check engine light remains on. We hooked it back up to the diagnostic system and was advised that another CO2 sensor is bad and that #5 is still mis-firing. We have already spent over $1,000.00 to repair this and we STILL cannot pass emmissions. Anybody have any ideas to help? PLEASE.
Tuesday, March 18th, 2008 AT 5:12 PM

2 Replies

Tiny
SERVICE WRITER
  • MECHANIC
  • 9,123 POSTS
IF you were in NY you would have got a waiver because of what you spent attempting to fix it.

It doesn't surprise my on the O2 sensors that another one came up bad. They compare values against each other and when one gets below it's threshold and gets replaced, the new one and an old one become too far apart in values.

You need to get that fixed.

The misfire is appeatently not a lack of spark as the wires and plugs were just changed. I would check the compression to see if it is lacking compression next.

Hopefully after thses problems are solved, you won't get an evap code as that monitor will not run until these are solved.
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Tuesday, March 18th, 2008 AT 5:21 PM
Tiny
ANPHON
  • MEMBER
  • 9 POSTS
I have a 1999 tahoe. I had the same exact problem you have. I did the same thing you did as far as trying to fix the problem. After spending over 800.00 dollars for censors to be replace the problem is now fix. I was told by a machine that you have many censors in these trucks. He said the censors talk to each other (in a sense) when the engine light comes on, it's because they're not hearing each other and the communicate is not getting through. So i'm thinking you're in the right area looking at the censors. I hope I help you a little.
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Monday, March 24th, 2008 AT 1:01 PM

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