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2006 chevy trailblazer_lt
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Discussion Starter · #1 ·
I have a 2006 Trailblazer. I am looking for step by step instructions to remove and replace the catalytic converter.
When I started it, there was a faint smell of rotten eggs. There is lagging upon acceleration...not all the time but it happens enough to need to fix it.
Check engine light is on. O2 sensor is only 3 months old. MPG is lower than it should be.
Answers, ideas or suggestions welcome.
 

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2003 gmc envoy_slt
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Well the first thing I would suggest is that you get the codes read.

Replacing expensive parts just because you feel it could be that is not something I could afford.

If the code is a P0420 , catalyst below efficiency, it could very well be a clogged cat, causing poor performance, or simply at cat that past it's prime. But that said, even if you DO have that code, it doesn't mean that that is your lack of power. That said, the cat could still be plugged and you get no P0420, but maybe a code for a MAF.

Lots of reasons for low power, need to start with the codes.

You also should have a scanner that can read real-time data so that we can help you narrow down where the problem is.

Android phone? You can get the Torque app & an OBD adapter for under 20 bucks that will do much more than you need.
 

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I don't have a screenshot of the Torque app post-cat O2 sensor.

This is what the pre-cat B1S1 should look like in Torque

Bank1 Sensor1
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The post-cat O2 sensor on a scanner, or Torque app will be called B1S2, for Bank1 Sensor2. Sensor 2 is always a post-cat oxygen sensor.

Each scanner will graph the voltage readings a bit different, this is another app screenshot showing the post-cat graph on the top, and the pre-cat on the bottom. The post-cat readings will usually appear "stair stepped" or as a much slower oscillation.


You can buy the ELM327 OBD2 adapter on eBay for under $15, or Amazon
This is the one to buy. I've tried several and this one is the most versatile and reliable. Some others won't always work on all vehicles, and some won't stay connected.
 

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2006 chevy trailblazer_lt
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Discussion Starter · #5 ·
I received my Bluetooth OBD scanner today and ran the diagnostics. I got the TC P0135 which is the o2 sensor. I also hooked up the fuel pressure tester and got 55PSI so that looks good.
The problem with the vehicle is, when I start driving, after a little while a warning light comes on and then I am unable to accelerate. I will pull over and restart the engine and it will drive just fine. Can this 02 sensor cause that?
I didn't download the Torque app but the OBDlink app that was advised to use. I don't know how to save the report or send it to me but I do have some snapshots if you want to see those.
 

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Registered
2006 chevy trailblazer_lt
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16 Posts
Discussion Starter · #6 ·
Well the first thing I would suggest is that you get the codes read.

Replacing expensive parts just because you feel it could be that is not something I could afford.

If the code is a P0420 , catalyst below efficiency, it could very well be a clogged cat, causing poor performance, or simply at cat that past it's prime. But that said, even if you DO have that code, it doesn't mean that that is your lack of power. That said, the cat could still be plugged and you get no P0420, but maybe a code for a MAF.

Lots of reasons for low power, need to start with the codes.

You also should have a scanner that can read real-time data so that we can help you narrow down where the problem is.

Android phone? You can get the Torque app & an OBD adapter for under 20 bucks that will do much more than you need.
I received the scanner and ran a diagnostics. The only code that came up was P0135 which is the oxygen sensor. When I figure out what the part number is I'll order that tonight. I'm not so sure that this bad sensor could be the problem I originally posted but I"m hoping so.
 

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2003 gmc envoy_slt
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The P0135 is for the heater for the sensor. "Most" times it is a failed sensor, but it can also be a bad ground for the sensor, or a corroded connector.
It's not a bad idea to replace the sensor first as in most cases these sensors never get replaced as often as they should. A new sensor response quicker than a high mileage sensor and can improve fuel mileage and lower emissions.
 

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Discussion Starter · #8 ·
It was Bank 1 Sensor 1.
The local auto store asked if it was an upstream or downstream.
I didn't know so I didn't buy the one he tried t o sell me for $106.
2006 Tailblazer LT 4.2L
Would you help me out with a part number for AC Delco or Denso?
 
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