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2002 chevy trailblazer_ls
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7 Posts
Discussion Starter #1 (Edited)
Hello, This is my first post here, so I first want to greet you. Second, I want to say I have been a GM fan all my life-due to my father's influence (who drove/drives a '94 Sierra, '03 Avalanche, '09 Silverado). I have driven several vehicles in the short time I have been driving ('98 Ford Ranger, '00 Pontiac Grand Am, '06 Nissan Altima, '98 Nissan Frontier). This last spring I bought a 2002 Chevrolet Trailblazer.

It had 170,000 miles at the time and the infamous rough idle. It also revved up funny when I applied just a small amount of pressure to the gas pedal. I'm pretty arrogant about fixing stuff, and I got the vehicle for a good deal (IMO). So I decided I would buy it and try to fix this problem. I know some have said this solution has not worked for them, but I may challenge the order of which they did these tasks (or that it is some other cause of a misfire). So here we go.

First, I unplugged the battery (negative and positive terminals, negative first) completely. Then I removed all six spark plugs and replaced them with Bosch Iridium spark plugs. Then I cleaned the throttle body as well as I could with generic carb spray from the auto parts store. After letting the Trailblazer sit a day, I plugged up the battery and started it up.

I have had no issues since. So for me, cleaning throttle body, replacing spark plugs, and letting it sit without battery for an extended time worked. I did do a little cleaning and tightening along the way of various parts of the motor, but nothing major. So maybe this post can help someone else in my shoes, because I am telling you, the shake was so bad I really lost my love for GM during that time.

If you have questions about procedures or tips, feel free to ask. I am a regular dude that doesn't know much about cars, so I can probably relate to most people.
 

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2004 gmc envoy_slt
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2,468 Posts
Glad you solved your problem.

The spark plug of choice among members is AC Delco 41-103 Iridium, our engine seems to like these.

When you cleaned the TB did you take it off and clean the back side as well?

If you don't know the maintenance history, you should change out the front and rear differential fluids and the transfer case fluid. Make sure to use AutoTrak II for the TC.

Sorry, didn't see you had a 2DW truck, never mind the TC fluid.
 

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2002 chevy trailblazer_ls
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7 Posts
Discussion Starter #3
Thanks and Yes

Yeah, I understand that AC Delco spark plug has been the spark plug of choice by many people. I don't think I have solved anything by using the Bosch one. I just know I have used the Bosch ones in other vehicles before with no issues, and their total was $29 (for 6), while the AC Delco ones' total were around $60. So price is basically the only reason I went with the Bosch ones. When/if I have problems with the Bosch ones, I may be wishing I had listened ha.

Yes, I did take the throttle body off and clean both sides.

No worries about the TC fluid. I appreciate your intent to help.
 

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2002 chevy trailblazer_ls
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Discussion Starter #5
Time

How many days /miles have you gone since fixing the problem?
Hey Joel,
I have only completed this solution as of last Sunday, September 21, (when I posted it). Since then, I have driven it for one week (or roughly 50 miles). So I have not driven it long, but it has been great during this time!
 

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2002 chevy trailblazer_lt
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3 Posts
It has been about 6 months now and I was just wondering if your TB was experiencing any issues regarding this fix. I'm having what feels like misfiring but not throwing any codes. I changed my plugs (AC DELCO 41103) about 15k miles ago but never did a TB cleaning.
 

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2002 chevy trailblazer_ls
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Discussion Starter #7 (Edited)
It drove great for five months. Then I sold it. So I sold it one month ago. It was driving great at the time, no codes or shakes.
 
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