1997 Chevy Suburban 02 Sensor Codes

Tiny
ANDETRAJ
  • MEMBER
  • 1997 CHEVROLET SUBURBAN
  • V8
  • 4WD
  • AUTOMATIC
  • 19,000 MILES
My '97 Suburban seems to have no power. It has the 5.7L Vortec. I purchased it this way for little to nothing, thinking it was the transmission, and figured I would drive it until the transmission went completely out, then replace it, but it still has not gone. I have put nearly 10k miles on it since I purchased it. With the lack of power, it just took a while to get up to speed, so I just lived with the problem since it was my secondary vehicle and barely drove it. I am starting to drive it now more because its winter and 4x4. I am beginning to think it is not the transmission now. When I accelerate, it feels like there is nothing there. When I push on the gas pedal, the RPM needle does not "jump" like it should. I can get up to speed, but it takes a while if I nurse the pedal. It appears that the transmission is shifting smoothly, almost flawlessly, going through all of the gears, unless you push the pedal to the floor. I have to let off the gas for the trasmission to shift into the next gear at WOT when the RPM gets to the shifting point. Even at WOT, the RPM does not move nearly as fast as I think it should to get to the shifting point. There is no passing power, as I cannot push the pedal to the floor to get the proper response. I had not received any SES lights until the other day. It was cold, possibly under 10 degrees, and I was having a hard time getting up to speed. The engine shuttered at around 40-45 MPH and the SES light came on. I checked the codes with my OBDII tester and got these two codes: P0131 and P0151. Once this happened, the vehicle appeared more sluggish than normal. I could barely get past 45 MPH after this, with almost no engine response from the gas pedal. The codes were then cleared by me. After the vehicle was turned off and sat for a while, it returned back to its "normal" state where it still took some nursing to get up to 65, but it still got there. It has never returned to the 100% normal state. Some days are better than others. I received another error code just yesterday, which was just P0141, and not the other two. My friend was driving the vehicle at the time and said that he did not feel it shutter and that he believes the light just came on. When the vehicle is in park, I can push on the pedal and the RPM needle moves as it should (with maybe a little sputtering?) And it feels like there is proper air flow through the exhaust (according to a friend who is more car savy than me). I use Super Unleaded (ethanol) gasoline. I'm not sure if that information helps at all. What are some possible cures to the problem or problems I am having?
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Thursday, January 7th, 2010 AT 3:36 PM

3 Replies

Tiny
SERVICE WRITER
  • EXPERT
Sounds like you might have a couple problems going.
It is possible that both symptoms are related.
If it were mine, based on the O@ codes you have, I would replace ALL of them. Not uncommon to have them all weak, but some only weak enough to set the code. Because they are compared to each other by the pcm, the next weakest one will set a code after the first offender was replaced.
This may resolve all of it. Certainly should for the second part.

If problem(s) are still present, I would be looking at these:

What is the fuel pressure?

Unplug the MAF and drive it, does it change the symptoms?

Pull the plugs and pay attention to what cylinders they came out of. Do they look normal?

Have you changed the fuel filter?
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Thursday, January 7th, 2010 AT 7:54 PM
Tiny
ANDETRAJ
  • MEMBER
I went for the cheapest thing first and I changed the fuel filter. When I pulled the filter and drained it into the snow, the snow turned black, not sure if thats normal or not. I could barely blow into the filter. When I did blow into it, it sounded like solid material came out, but could not tell for sure because whatever came out landed on a dirty concrete floor. After changing it, there was proper throttle response at any speed. It seemed like the vehicle had power, something its never had since I've owned it. I could press on the accellerator at 60mph and it would shift gears and accellerate quickly. After driving for about 20-30 miles, it almost returned to the way it was before I changed the filter. It lost proper throttle response, but is still not as bad as it was before changing the filter. Before changing the filter, if I would aggressively rev the engine, the RPM needle would immediately drop and kill the engine. If I would rev it slow, it would rev appropriately. The first time I started it after chaning the filter, I aggressively revved the engine and it did not hesitate and kill. Now, after driving it a while, if I aggressively rev the engine, it hesitates for approximately a half second, then revs normally, but does not kill like before. Thoughts?
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Sunday, January 10th, 2010 AT 3:43 AM
Tiny
SERVICE WRITER
  • EXPERT
Knowing the fuel pressure when the problem is happening would be good. Plugged fuel filter can damage a pump and it may be weakened. The filter was certainly on problem.

Since there still is an O2 code situation, The symptoms may be returning because of bad O2s.

Once the engine comes to temp and the O2s are activated, they may be reporting false data causing the pcm to make incorect adjustment to the A/F ratio.
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Monday, January 11th, 2010 AT 5:01 AM

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