After the engine warms up, the ECM goes into closed loop mode and then uses the O2 sensor readings to adjust fuel delivery (among other things). When an O2 sensor packs it in, the ECM falls back to a predetermined operating mode to keep the engine running (usually with poor fuel economy). This does not usually trigger the "reduced power" setting - if the ECM detects another serious sensor problem, it will put the engine in "emergency" mode to give you the means to get to a shop for repair. I strongly suggest you check for trouble codes with a code reader before attempting any repairs.
I am going through the same issue. I'm going to replace all of the o2 sensors and hopefully this will solve the issue. From what I've read, it should. All of the sensors are located on the exhaust system, as I've read from previous posts, and from what I've seen when I look up 2004 Chevy Tahoe 5.3 L oxygen sensor location images. I hope this helps you!
You have a tahoe also ? with reduced engine power ? This is a problem with the drive by wire - electronic throttle control ,not the O2 sensors.
The throttle actuator control (TAC) system delivers improved throttle response and greater reliability and eliminates the need for mechanical cable. The TAC system performs the following functions:
• Accelerator pedal position (APP) sensing
• Throttle positioning to meet driver and engine demands
• Throttle position sensing
• Internal diagnostics
• Cruise control functions
• Manage TAC electrical power consumption
The TAC system components include the following:
• The APP sensors
• The throttle body assembly
• The TAC module
• The powertrain control module (PCM)
With reduced engine power message - codes are stored ,hook up a scan tool an check codes https://www.youtube.com/watch?v=Vus2srgv...
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SOURCE: 04 chevy tahoe
the check engine light you are getting sounds like and electrical problem, have the battery and the alternator tested, and have autozone or the like pull the codes off for you and see if you can figure out what they are....
SOURCE: 2004 Chevy Tahoe - Reduced engine power message
have autzone check for any stored trouble codes, replace the fuel cap, make sure you have plenty of gas
SOURCE: 1995 Chev S10 4.3L V6 rough idle and under power
This make/model has a chronic problem with EGR clogging. If you have a dashboard indicator showing "check engine" most likely it is a trouble code indicating and EGR (exhaust gas recirculator) valve problem. Symptoms are rough idle, and surging and stalls.
What happens is sediments from the exaust manifold get sucked up into the valve when it opens, then stick in the valve and keep it from closing. When the valve is open when it should be closed, the engine runs very rough.
I removed my egr and then dislodged the sediment (pea-sized debris) and then re-installed the valve. Three days later, the same "check engine" and same rough idle. I must have did this at least three or four more times.
What I found that gave me a permanent solution was an aftermarket filter gasket that keeps debris from clogging. I don't remember the name of the product, but a search for "EGR filter gasket" may lead you to the product.
Install the gasket between the EGR and the exhaust manifold and you should be good to go. Note: on 1995 and newer models, disconnecting the EGR from the wiring harness (common on R&R) may require the computer to be reprogramed.
SOURCE: Rattle/Shake during normal use, Rough Idle
1996 ,wow its classic its over 10yrs of age ,,,,,,renew it sounds like engine is finished
SOURCE: 2004 subaru forester, 99,000 miles. Check engine
Drop in to an Autozone, or Pep Boys, or similar big parts store & they will usually scan for codes free. This will hopefully eliminate all the guess work, or at least point everyone in right direction for better diagnosis. If not obvious from codes what the problem is, get back to us and we'll help you out.
Testimonial: "Thanks for the great suggestion . I'll have Autozone read the codes on Monday. Thanks again!"
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