Skip the auto shop - Our mechanics make house calls

Q: my car is slow to accelerate. i have a p0171 code. i replaced my o2 sensor but the code came back on. what else could it be?

asked by on

my car is slow to accelerate. i have a p0171 code. i replaced my o2 sensor but the code came back on. what else could it be?

My car has 230000 miles.
My car has an automatic transmission.

A: The code P0171 is a lean code indicating th...

The code P0171 is a lean code indicating the O2 sensor is detecting the engine is running lean – that is, the air/fuel mixture is imbalanced. You may have a clogged fuel filter or a fuel pump that is not supplying enough fuel pressure. You will need to have the fuel pressure and volume checked with a fuel pressure gauge. You can try to replace the fuel filter to see if it helps first. Your best thing to do is to have a mechanic diagnose the problem and check the fuel pressures and filter. Also make sure your air filter is clean and the inlet air tube is not cracked or loose.

Check these items, and if you still need assistance, contact a professional mechanic. A certified mobile mechanic from YourMechanic can visit your home or office to inspect your vehicle's acceleration issues.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: How do I check the brake fluid?

Your car’s brakes are the most important safety system onboard. They’re hydraulic, which means they require fluid in order to operate. When you press the brake pedal, fluid is sent from the master cylinder through the brake lines to the...

Q: Getting error codes P0599 and P0171. Ive cleaned the O2 sensors but have no idea where to go from here.

Hello. Code P0599 is the code for an issue with the thermostat heater control circuit, while P0171 is for a lean condition on bank 1. P0599 is set when the computer detects that there is an issue with the electronically...

Q: About the key

Hey there, thanks for writing in. If you are having trouble with your key, I would recommend taking the car to the Toyota dealership to have the key reprogrammed.

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...