Q: My check engine light is on reading code po171 lean

asked by on

My check engine light is on reading a code of po171 lean. Sometimes when I accelerate it hesitates like if your riding a horse or in a boat swaying front to back but this rarely happens but it still happens. I also have some kind of fluid I believe to be oil coming down and covering the bottom of my engine. No other problems besides lack of alot of power when accelerating and that oil on the bottom. I also just replaced the mass flow sensor and got an oil change. Any thoughts?

My car has 171000 miles.
My car has an automatic transmission.

The code P0171 is for the engine control module is getting an O2 sensor lean bank 1 problem in the engine and has tried to compensate by making the injection system go rich on that bank. There is a long list of possible causes like intake bolts loose, injectors sticking, vacuum leaks, clogged injectors, carbon buildup on injectors or valves. The list goes on. You will need to have the pinpoint test performed to diagnose the problem and code to see if there is a sensor issue or a problem with another engine component. The oil leaking may have got on the O2 sensor and caused a bad reading. If this is the case, then the oil leak and O2 sensor will need to be repaired. I recommend having a mechanic come to your home or office to give the Check Engine Light a thorough inspection to ensure appropriate repairs are made.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. My check engine light is on reading code po171 lean

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Stopped accelerating and shaking at highish speeds?

Hello, thank you for writing in. The first step is to find out what issues are triggering the check engine light. This can be done by having the vehicle scanned for diagnostic troubleshooting codes at your local auto parts store,...

Q: My car has a rough idle and when you step on the gas it falls on its face and then takes off

The engine ignition system should be checked for misfires and fouled spark plugs and shorting plug wires. Have the engine computer scanned for any stored codes for the MAP sensor on the engine intake. These are know to fail and...

Q: Slow acceleration and engine light on/off

A sealed transmission should have nearly no loss of fluid. An overfilled transmission can also cause issues. The fluid level and condition should be checked to ensure the fluid is at the proper level. This will require a scan tool...

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...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...