Last reported case: 1 months ago
Based on 4 owner reports (1 from Reddit, 3 from forums)
What is P0171?
P0171 indicates your engine's Bank 1 is running with too much air and not enough fuel, which is called a 'lean' condition. This is a medium-severity powertrain issue that can reduce fuel economy and performance, and it's commonly triggered by vacuum leaks or faulty sensors. Based on 551 reports, repairs for this code average $4596, with Ford Mustangs and F-150s being among the most frequently affected vehicles.
Common Causes:
- Vacuum leaks in intake hoses or gaskets (reported in numerous discussion clusters)
- Faulty mass airflow (MAF) or oxygen (O2) sensors
- Clogged or failing fuel injectors
- Fuel delivery issues like a weak fuel pump or clogged filter
Symptoms:
- Check Engine Light is illuminated
- Reduced engine power or hesitation during acceleration
- Poor fuel economy
- Rough idle or engine misfires
🚗P0171 on 2010 FORD Mustang
This page focuses specifically on P0171 issues reported by 2010 FORD Mustang owners. The experiences and fixes below are from real owners of this exact vehicle.
Symptoms Reported by 2010 FORD Mustang Owners:
Parts Often Involved:
What Owners Say
Real experiences from 2010 FORD Mustang owners
“Edit: Turns out this time the codes were P2004 and P2005. So more than likely the my issue is the intake manifold isn't functioning properly causing the P0171 code.”View original
“Hey everyone, I got a 2006 Mustang GT and keep having code P0171 pop up. Ive checked for leaks (nothing to be found) replaced the fuel injectors, changed the fuel pump, checked the o2 sensors, and cleaned the Mass Air flow sensor but the code keeps popping up.”View original
“Its really frustrating because I cant sit in my car and have the heat on for too long, otherwise the gas smell will take over the cabin.. When I drive, the smell goes away, even when the heater is on, but when idling, its there.”View original
“My mechanic came down to the probability that it might be the MAF sensor that needs replacing. I figured I'm gonna take it to another mechanic to get a second opinion cause if I go back to that one he'll charge me $300 to replace the part including the part.”View original
“I dont see any leaks either, so what is causing this? Its really frustrating because I cant sit in my car and have the heat on for too long, otherwise the gas smell will take over the cabin..”View original
“Hey everyone, As of Saturday PM, I am the proud owner of a 2010 Mustang GT Premium Convertible!! She has about 65,000 miles on her, and I intend to keep the mileage very low as it is a second, fun car.”View original
“She has about 65,000 miles on her, and I intend to keep the mileage very low as it is a second, fun car. Prior to my purchase, I had a Ford Dealership in Arlington, VA inspect the car.”View original
“I've taken it to a mechanic and ran a diagnostic. There was a vacuum leak and he replaced the power brake hose that runs from the brake booster to the intake manifold.”View original
These are real experiences shared by 2010 FORD Mustang owners on automotive forums and communities. Results may vary based on vehicle condition and repair quality.
About This Data
This page aggregates 4 discussions about P0171 from 2010 FORD Mustang owners across automotive communities.
Success rate (25%) is calculated from posts where owners confirmed whether their fix resolved the issue.
Last updated: 1/19/2026