[SOLVED] 03 Envoy Loss Of Power - Not Sure Why? - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum



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Go Back   Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum > 2002 - 2009 TrailBlazer/Envoy Tech > 02-09 Vortec 4.2L I-6 Engine and Drivetrain > OEM Issues

OEM Issues Original Equipment Repairs and/or Problems

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  #1  
Old 01-02-2013, 10:43 AM
gstump gstump is offline
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2003 GMC Envoy SLT XL
Pewter Metallic 4.2L I6 AWD
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03 Envoy Loss Of Power - Not Sure Why?

We have a 2003 Envoy XL SLT 6 Cycl 4x4. 130K miles. Just in the last few days or so I have noticed that it doesn't have all the power that it used to have. Manily I notice it when going uphill as it's now having to kick down a gear to climbs hills it could do in a higher gear before. Also not as fast off the line. I did a search here but only see where people are getting a warning light that says "Loss Of Power". I'm not getting a warning light...just the actual power loss.

I cleaned the throttle body a few months ago and changed plugs while I was in there. Had the fan clutch go out a few years ago so I don't think that's the issue and it's been cold here but certainly not east coast cold :-) Air cleaner was recently replaced. Both differentials and tranny have recently had fluids changed. Figure I will need to purchase something that will read codes but in the meantime I was just wondering if you guys could suggest things to check?

UPDATE: After researching this some more I'm thinking it might be a clogged cat so I am going to test that by removing the O2 sensor and seeing if it runs better. Will post follow up.

Many thanks in advance!

GS
West Linn, OR
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  #2  
Old 01-04-2013, 01:02 AM
bspurloc bspurloc is offline
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2002 GMC Envoy SLT
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Quote:
Originally Posted by gstump View Post
We have a 2003 Envoy XL SLT 6 Cycl 4x4. 130K miles. Just in the last few days or so I have noticed that it doesn't have all the power that it used to have. Manily I notice it when going uphill as it's now having to kick down a gear to climbs hills it could do in a higher gear before. Also not as fast off the line. I did a search here but only see where people are getting a warning light that says "Loss Of Power". I'm not getting a warning light...just the actual power loss.

I cleaned the throttle body a few months ago and changed plugs while I was in there. Had the fan clutch go out a few years ago so I don't think that's the issue and it's been cold here but certainly not east coast cold :-) Air cleaner was recently replaced. Both differentials and tranny have recently had fluids changed. Figure I will need to purchase something that will read codes but in the meantime I was just wondering if you guys could suggest things to check?

UPDATE: After researching this some more I'm thinking it might be a clogged cat so I am going to test that by removing the O2 sensor and seeing if it runs better. Will post follow up.

Many thanks in advance!

GS
West Linn, OR
I was just going to say.... "It sounds like a clogged cat" just went through this at 150k.
Dont forget KEEP the old cat as it is worth around $50 for this vehicle. If you dont know any local places that will buy it there is ONLINE ones that will pay the shipping and you for it.
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  #3  
Old 01-06-2013, 12:14 PM
gstump gstump is offline
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2003 GMC Envoy SLT XL
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cat replacement

OK....removing the O2 sensor appears to make it respond to the pedal much better. I am concerned about driving it that way because there is some sort of wire there across from the O2 sensor hole that I don't want to get fried if I drive it so I just placed a heat shield over that (OK it's a grill plate from my BBQ :-) and rev'd it in the garage. I'm convinced enough that I purchased a new Walker direct fit cat and am going to replace it today. Was supposed to do yesterday but (conveniently) found way to many other things to do.

Will post follow up.
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Old 01-07-2013, 11:54 AM
gstump gstump is offline
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Power restored!

OK. Cat replaced & power restored. The temp will not go past the 2nd mark on the gauge so I'm assuming I need to replace the stat & sensor. In process...will post back. Am also starting a new thread about the cat replacement while it's fresh.
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  #5  
Old 01-08-2013, 04:55 PM
bspurloc bspurloc is offline
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Originally Posted by gstump View Post
OK. Cat replaced & power restored. The temp will not go past the 2nd mark on the gauge so I'm assuming I need to replace the stat & sensor. In process...will post back. Am also starting a new thread about the cat replacement while it's fresh.
supposedly a bad Thermostat kills the Cat
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  #6  
Old 01-08-2013, 04:58 PM
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Ray Dockrey Ray Dockrey is offline
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Originally Posted by bspurloc View Post
supposedly a bad Thermostat kills the Cat
It will but the problem on 02 and 03's is that they used to small a cat. The 04 and ups have a bigger cat which solved the issue. That is why almost always when you hear people talking about a bad cat on these vehicles it is an 02 or 03.
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  #7  
Old 01-08-2013, 05:05 PM
bspurloc bspurloc is offline
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2002 GMC Envoy SLT
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Originally Posted by Ray Dockrey View Post
It will but the problem on 02 and 03's is that they used to small a cat. The 04 and ups have a bigger cat which solved the issue. That is why almost always when you hear people talking about a bad cat on these vehicles it is an 02 or 03.
we cant just install a larger cat on these? Ah well mine went at $150k cant really complain
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  #8  
Old 01-14-2013, 09:56 AM
gstump gstump is offline
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2003 GMC Envoy SLT XL
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Stat replaced and temp back to normal. Stat was also a PITA thanks to design and will post thoughts on that separately.
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