2000 Pontiac Gran Prix, 119,000 miles, check engine light comes on after heavy, extended acceleration, both codes P0131-low voltage O2 sensor bank1, sensor1 and P0137 -low voltage O2 sensor bank 1, sensor2 are set every time. I have replaced gas cap and run Fickt injector cleaner through last tank of gas. I would replace a defective O2 sensor, but, since both fault out every time, there must be something else going on.
Country: United StatesMake: PontiacModel: Grand Prix GTYear: 2000Engine: 3800
Replaced gas cap,run injector cleaner through and checked exhaust system for leaks or plugged converter, nothing obvious found
Hi,welcome to Just Answer.I will be happy to assist you with this question today.I will try and assist you as best as possible from here,feel free to ask any follow up questions to my info provided here.
The oxygen sensors are actually seeing a lean condiiton when they read low voltage like this.This can sometimes be caused by a plugged fuel filter or a weak fuel pump.
The fuel filter needs replaced once a year or every 15,000 miles whichever comes first,if this hasnt been done recently then this should be replaced.If it has been replaced then the next step would be to have the fuel pressure tested to see if it is low/weak.If it is then most likely the fuel pump needs replaced.
I would also have the engine checked over to make sure there are no vacuum leaks as this will also cause this and also have the mass air flow sensor cleaned in case it is registering incorrectly.
All of these can cause this type of fault here.
Let me know if you need anything else with this question asked here.Thanks Pete!
15 Years Pontiac Technician and training.
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Hi Terrance,I'm just following up with you to see how everything is going. Did my answer help?Let me know,Pete
Your answers were helpful and spot on. Replaced the fuel filter last night and got 43 psi on the fuel rail. Will see how she runs now, fuel pump may be the next project.
Thats great to hear.Let me know if you need anything else in the future.Thanks Pete.