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Discussion Starter #1
04 TB, 4.2 engine. Codes P2135, P2101, PO4555. I replaced the air horn a year ago, ran fine until a month ago, replaced throttle pedal assy a month ago. I can drive the TB for a while, then goes into reduced engine power. I can turn off ignition, restart, and all is good for a while, sometimes a week or more, sometimes a few minutes. Code P2135 tells me either the throttle pedal or air horn not connected. P2101 relates to about the same thing. PO455 is excessive air flow in EGR. I did notice the cat con makes a rattling sound like a loose baffle. A friend tells me that is the whole problem. I don't want to replace the whole cat con and pipe if it is not needed. I already have about $300 in the air horn and throttle. This TB is getting to be a pain in the ass, costing more money than the damn thing is worth. It only has about 130K miles on it. What can cause all these problems???
 

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P0455 is an EVAP code, could be a poor sealing gas cap, Could be a crack in the fill pipe.

The other two are codes related to the throttle body sensor knowing where the gas pedal is positioned.
If you changed most of the parts, look for damaged wiring/poor joints between the throttle and the ECM and between the throttle body and the ECM.

I assume when you talking "air horn" your talking about the throttle body!
 

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23 looks and no answer. Are there any knowledgeable TB people out there???
One of the reasons you havent gotten responses is because you have NO truck info in your post. Is this a trail blazer, a colorado???????. You have no truck info in you profile page, just a pic of a cool 30s ford. This is a truck forum. We are all truck owners like you. We share what we know and have learned from doing our own repairs, for the most part. A few of us do have experience as a mechanic,but all cars and trucks change and get more complex every year. All of the manufactures do not want you working on you vehichel your self. It takes special training and tools to keep up with each model. So if you want help in the future, please put all your truck info in your post, along with engine, trans info, ect. 4.2 what, is this a inline 6 cylinder? Did you make a typo and is it a 4.3 V 6? All of this being said, your in good hands with Ray.
 
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Kenny I think he means a 2004 trailblazer when he says a TB. I had one at one time and it was an inline 4.2L 6 cylinder. I don't believe there was a 4.3 v6 in those but a v8 was available in the EXT.
Jerreich, Code P2135 is a problem most likely at the throttle body sensor. The PCM directs the throttle body motor to open and close the throttle plate in response to the Gas pedal position.
When the PCM sees a difference in reference voltages from the gas pedal and the reference from the throttle position sensor (mounted on the side of the throttle body) it sets this code. Any problems with the 2 sensors or the wiring between them and the PCM will set this code. You will need to check the reference voltages from each sensor with a voltmeter. Use this link for more info. https://troubleshootmyvehicle.com/gm/4.2L/electronic-throttle-body-tests-1
 

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Kenny I think he means a 2004 trailblazer when he says a TB. I had one at one time and it was an inline 4.2L 6 cylinder. I don't believe there was a 4.3 v6 in those but a v8 was available in the EXT.
Jerreich, Code P2135 is a problem most likely at the throttle body sensor. The PCM directs the throttle body motor to open and close the throttle plate in response to the Gas pedal position.
When the PCM sees a differenc in reference voltages from the gas pedal and the reference from the throttle position sensor (mounted on the side of the throttle body) it sets this code. Any problems with the 2 sensors or the wiring between them and the PCM will set this code. You will need to check the reference voltages from each sensor with a voltmeter. Use this link for more info. https://troubleshootmyvehicle.com/gm/4.2L/electronic-throttle-body-tests-1
Lol well I guess Im the D.A. then ha ha
 

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Jerreich, additional info. I highly recommend that you use an analog volt/ohmeter for the above tests.
 

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Discussion Starter #8
Rayvoy, thank you for your input. I sort of suspected a poor connection, but assumed that the connecter plugs were foolproof. That seems to be the logical problem if I can shut engine down, restart and go for a while. Silverado002, the link you put in your answer is what I was looking for. I looked thru all the previous posts on this forum looking for that very info. Thank all you guys for your input, even Kenny.
 

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Rayvoy, thank you for your input. I sort of suspected a poor connection, but assumed that the connecter plugs were foolproof. That seems to be the logical problem if I can shut engine down, restart and go for a while. Silverado002, the link you put in your answer is what I was looking for. I looked thru all the previous posts on this forum looking for that very info. Thank all you guys for your input, even Kenny.
Most of us just look at the new post. My bad, I sould have looked at where you posted. I would have seen the post is where it belongs, in the trailblazer forum. So please forgive my previous post. I am at work looking at this, (when I should working, but it is a little slow rite now) so I sometimes over look things.
 
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