Reduced power

Tiny
JLAHAIE83
  • MEMBER
  • 2007 CHEVROLET TAHOE
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
About a month ago it had the code engine reduced power service stability track and service traction control. It has been running rough the transmission shifts really hard. I have read a lot of forums and I said it could be the throttle body sensor. So I replaced that and I have replaced the catalytic converters. I replace the muffler or replace the spark plugs and wires and the mass flow air sensor. Now every once in a while clean up and run fine, but then it just goes back to running rough and has no power at all. It almost sounds like a Subaru when it is having this problem.
Thursday, January 12th, 2017 AT 4:50 PM

22 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Go to an auto parts and have them scan for codes. then get back to us. also, rent fuel pressure gauge and see what it is. see link.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

and

https://www.2carpros.com/articles/engine-has-low-power-output

Please let us know what happens so it will help others.
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Friday, January 13th, 2017 AT 7:14 AM
Tiny
LOU P
  • MECHANIC
  • 118 POSTS
With that many miles I also would suspect a fuel pump. It sounds very much like you are lacking fuel pressure. Lou
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Friday, January 13th, 2017 AT 7:21 AM
Tiny
JLAHAIE83
  • MEMBER
  • 11 POSTS
My wife had them check the codes when it first started doing this and there was about 50 or so but I'm going to save up some money and rent the fuel pressure tester and go from there
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Friday, January 13th, 2017 AT 3:40 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
If there are 50 codes then have battery checked for condition including load test most places do for free. A low battery will do this then if still codes, erase them and start over
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Friday, January 13th, 2017 AT 4:26 PM
Tiny
JLAHAIE83
  • MEMBER
  • 11 POSTS
Something happened right before this problem happen a wire going to the main harness fried we replace the wire and it ran fine for a little while and then it started doing this and my batteries are brand-new I have dual yellow top Optima is in it
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Friday, January 13th, 2017 AT 5:33 PM
Tiny
JLAHAIE83
  • MEMBER
  • 11 POSTS
I have 52 psi of fuel pressure I am stumped on what it could be please help
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Friday, January 13th, 2017 AT 8:47 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Now the real story happens, trace the fried wire to where it goes and what module it probably also fried that module or more.
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Saturday, January 14th, 2017 AT 6:09 AM
Tiny
JLAHAIE83
  • MEMBER
  • 11 POSTS
It happened when she drove up to Washington everything shut off and went dead nothing worked she had it towed to where she was going I added the other battery and I butt connected the wire that went from a Fuze on the firewall to the main battery I extended it with a heavy duty butt connecter and run it to the driver side battery mount and everything was fine for about 8 months the wire fried from the butt connector to the battery didn't even fry the Fuze or the stock wiring so she replaced the wire and the Fuze just in case and it started and ran fine for about 5 minutes or so then all this started
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Saturday, January 14th, 2017 AT 10:09 AM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Unfortunately because we don't know what fuse it is or wire we won't be able to help and probably this will need to be physically looked at as the ignition switch could have burnt or anything else. I'm afraid we can't help with this problem.
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-1
Saturday, January 14th, 2017 AT 1:11 PM
Tiny
JLAHAIE83
  • MEMBER
  • 11 POSTS
I know you said you can't help me but today I tested the fuel pressure again and it was at 58 PSI and according to my book it should be between 43 and 45 when the engines idling so do you think it's getting too much fuel
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Saturday, January 14th, 2017 AT 1:47 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Fuel pressure should be 50-60 psi your manual or book is wrong
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Saturday, January 14th, 2017 AT 1:50 PM
Tiny
JLAHAIE83
  • MEMBER
  • 11 POSTS
I have a Haynes manual
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Saturday, January 14th, 2017 AT 2:06 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
What I gave is correct
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Saturday, January 14th, 2017 AT 3:31 PM
Tiny
JLAHAIE83
  • MEMBER
  • 11 POSTS
Yes it is thank you I went back out there held the gas at 2000 RPM's for 10 seconds and then it would drop down to 1500 for about 3 to 4 seconds and then go back up to 2000 RPMs and it keeps doing that as long as I want to do it
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Saturday, January 14th, 2017 AT 3:33 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Clean the throttle plate on both sides and iac hole with choke cleaner, look for a vacuum leak then take to a mechanic so he can see this thing physically
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Saturday, January 14th, 2017 AT 4:38 PM
Tiny
LOU P
  • MECHANIC
  • 118 POSTS
I agree with having a mechanic check it , getting an issue to be consistent is the key, also you said you had a bunch of codes but you failed to post any of the codes here. It seems like you can move on from the fuel issue, you can have a gunned up throttle body as previously stated, or you can have excess raw fuel flowing from the evap system when the purge valve is a actuating or you can have a misreading mass air flow sensor or any other type of sensor failure but not having an idea of any stored or current codes really doesn't help us help you. Lou
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Saturday, January 14th, 2017 AT 4:45 PM
Tiny
JLAHAIE83
  • MEMBER
  • 11 POSTS
Yes I know not having any of the codes not helpful I wasn't with her when she got the codes read and I have cleaned the throttle body replaced the throttle position sensor and the mass air flow sensor so I'm going to have to try to clean the other things you guys were talking about thank you very much for your help
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Saturday, January 14th, 2017 AT 6:12 PM
Tiny
LOU P
  • MECHANIC
  • 118 POSTS
You can loan a scan tool from Autozone for free you just need to put down a deposit on the tool I believe.
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Saturday, January 14th, 2017 AT 7:15 PM
Tiny
JLAHAIE83
  • MEMBER
  • 11 POSTS
So I scanned it and cylinders 176 and 4 are not firing
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Monday, January 16th, 2017 AT 3:49 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Have a mechanic check this so he check injectors, sensors etc that will be your cheapest option.
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Monday, January 16th, 2017 AT 4:17 PM

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