Code PO171

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.

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,644 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

Code PO171

3 Replies

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