Skip the auto shop - Our mechanics make house calls

Q: When I press the gas pedal the vehicle misfires

asked by on

i connect launch scanner it show p1128

My car has 85654 miles.
My car has an automatic transmission.

The code P1128 means that the heated oxygen is swapped from the circuitry. Check the wiring on the O2 sensor and check the condition of the O2 sensor. If the sensor is working fine or you have replaced the sensor and the code still comes on, then there could be a problem with the mass air flow (MAF) sensor or a vacuum leak.

First, look for any vacuum leaks. Check all of the hoses that are connected to the intake manifold and see if there are any vacuum leaks. If there is a vacuum leak, then fix the leak and check if the code comes on. If there is no vacuum leak, then check the MAF sensor for any corrosion or debris. Remove the MAF sensor and clean it. Once it is cleaned, put the MAF sensor back on and retest. If the code comes back, then the MAF sensor is malfunctioning. If you need further assistance with your engine, then seek out a professional, such as one from YourMechanic, that can help you with the gas pedal issue.

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・Fair and transparent pricing

Get a quote

What others are asking

Q: What's the cost of ownership for an Audi?

Unfortunately it is not easy to predict what any car will cost to maintain. Problems can pop up even with vehicles that have reputations for great reliability just as easily as "luxury" brands that may not be well known for...

Q: Car won't stay started without gas pedal down

It sounds as though severe engine damage may have occurred, due to overheating. If a vehicle is allowed to overheat even once, extensive damage, such as a cracked cylinder head or blown head gasket, may result. However, before we assume...

Q: Missing and popping under heavy acceleration.

Popping back through the intake, along with misfires, is a sign that the engine is running lean (not enough fuel). Here are a few things to check: Check the fuel pressure: There is usually a port on the...

Related articles

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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.