Bad hesitation issues

CAOLAN

MEMBER
2005 CHEVROLET TRAILBLAZER
4.3L
6 CYL
4WD
AUTOMATIC
180,000 MILES

About 4 months ago I noticed that my vehicle started hesitating when I pressed on the gas, or just maintained the velocity manually or through cruise control. I saw that it is getting the P0135 error for the O2 Sensor which is the forward one.

The hesitation over the last couple of weeks has gotten worse and worse, and this last weekend I took it on a drive to see if the problem persists after cleaning the throttle body, which it desperately needed. During this drive, the engine shut off twice and in these two times I lost power steering and power brakes.

Another observation is that the engine is running a bit on the hot side. I checked the oil and coolant but there's plenty in it.

I am going to replace the O2 sensor this weekend, however I am wondering if these are other issues I need to investigate, or will a failed O2 sensor cause these kinds of problems?

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,513 POSTS

Yes, lets start with the oxygen sensor because they can cause issues. Here is a guide to help you replace it with the oxygen sensors locations in the diagrams below:

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

This guide can help as well:

https://www.2carpros.com/articles/engine-hesitates

Check out the diagrams (below). Please let us know what happens.

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Wednesday, July 31st, 2019 AT 1:33 PM

CAOLAN

MEMBER
5 POSTS

I replaced it today and it seems to have fixed the problems. I have driven it around in freeway, stop and go traffic, with and without cruise control and it doesn't have any hesitation. Also the loud BRRRRRRRRR sound it makes in the rear has gone away apparently.

What does the O2 sensor do that would affect the engine so much?

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Wednesday, July 31st, 2019 AT 2:01 PM

KEN L

MASTER CERTIFIED MECHANIC
47,513 POSTS

Glad you fixed it! the oxygen sensor monitor the exhaust mixture and provide feedback data for the computer. here is a better explanation of what they do:

https://www.2carpros.com/articles/how-an-oxygen-sensor-works

Use 2CarPros anytime, we are here to help. Please tell a friend.

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Thursday, August 1st, 2019 AT 10:45 AM