1999 Toyota 4Runner P0172 system too rich code (1 Viewer)

[borrhee]

Hello all, My daughter has a 99 4runner 2 wheel drive that has been giving her issues with the code of P0172 system too rich. She has been driving the car for a while with the check engine light on. I have changed the O2 sensors, MAF, knocker sensor, throttle position sensor, and the fuel injectors and still having the same issues. She was telling me that the gas millage was getting worse (that make sense when the car gave us the P0172 code) and then one day when she was driving the car just died and then the following morning I was able to start it up. Any advice would be greatly appreciated. Thanks

 

[gnob]

have you inspected the fuel pressure regulator and return line?
can you see the o2 sensor data?

 

[borrhee]

have you inspected the fuel pressure regulator and return line?
can you see the o2 sensor data?

Thanks for the reply. I have not inspected the fuel pressure regulator and return line. I didn't think about that. That is a great idea. I will try that next. I have an obd2 that will show me live o2 data but i don't know what correct data I am looking for when it comes to that.

 

[alia176]

What did you find out?

 

[borrhee]

What did you find out?

Sorry, its been busy and wet lately. I order the fuel pressure reg which should be in next week and then I will be able to install it. By then I should know more. Thanks for the follow up.