Code PO171

Tiny
BOOKERT1
  • MEMBER
  • 2004 MAZDA TRIBUTE
  • 3.0L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 198,000 MILES
Starts in the morning. Runs about 30 seconds and starts sputtering, if I give it gas it cuts out. Turn key off and it’ll start right back up. This happens 5-6 times then it’ll run perfect. Once driving it’s fine until I kick it into passing gear then it doesn’t have the power it should and when I take my foot off the gas it stalls. I pull over and it starts right back up. I was told to replace the Mass Air Sensor which I did but it didn’t help. I don’t hear any vacuum leaks. After it acts up it starts right back up and runs beautiful.
Thursday, February 13th, 2020 AT 12:35 PM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,077 POSTS
Hi,

The code indicates a lean fuel mixture. That can be a few different issues. The first thing that needs done is to check fuel pump pressure. Here is a link that explains how it is done:

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

Now, if fuel pressure is within the manufacturer's specs, then we need to check for a vacuum leak which could be allowing unmetered air to enter the engine.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Also, I will need to know if you hear an exhaust leak near the engine.

Here are the manufacturer's specs as far as fuel pressure:

2004 Mazda Truck Tribute 4WD V6-3.0L DOHC
Pressure, Vacuum and Temperature
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pump Specifications Pressure, Vacuum and Temperature
PRESSURE, VACUUM AND TEMPERATURE
Fuel Pressure

Fuel Line Pressure Max .................... 380-482 kPa (55-70 psi)

Fuel Line Pressure Engine Running .................... 240-380 kPa (35-55 psi)

Pressure drop after 1 min. .................... Less than 5 psi

Do this and let me know what you find. I have a feeling it is fuel pressure related.

Take care,
Joe
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Thursday, February 13th, 2020 AT 6:02 PM
Tiny
BOOKERT1
  • MEMBER
  • 1 POST
So I ended up taking it to a mechanic and had him change the fuel filter and that solved the issue. Thanks for your help.
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Saturday, February 22nd, 2020 AT 10:39 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,764 POSTS
Good to hear, please use 2CarPros anytime we are here to help.
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Saturday, February 22nd, 2020 AT 10:39 AM

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