Skip the auto shop - Our mechanics make house calls

Q: car jerks/gas pedal

asked by on

I have a 2004 Altima 2.5S (Automatic). The car slightly jerks when shifting gears (much more noticeable in downhills) and that's frustrating in traffic because the car wants to change gear from 1 to 2 but I press the brake and that's a bad jerk. I have taken the car to 3 transmission shops and they all did a road test and said there's nothing wrong with the transmission. Also No fault code exists. At idle (P) when I give some gas to 3000 rpm, the rpm needle sticks at around 1500 on return for 1-2 second, then comes back down to 900. Looks like the gas stuck somewhere in engine. I had already cleaned the throttle body but no relief! Have this issue for 8-9 mounts and that's not getting worse nor getting better. Only one or 2 times when I turned the A/C on, the problem went away and the gas pedal became enough stiff and satisfactory. I think this problem appeared after I changed my dead alternator myself.

My car has 138 miles.
My car has an automatic transmission.

Hi, thanks for writing in. This is more than likely a fuel delivery issue, given the symptoms you describe. The idle air control valve is a unit that regulates the air flow into the engine as it is mixed with fuel prior to being injected into the motor. When this is not working properly, this will cause an imbalanced load of air and fuel to be supplied to the motor resulting in a loss of power or stall as you have experienced. This may also cause the car to have an irregular idle as you have described. I would recommend having an expert from YourMechanic come to your home or office to confirm a diagnosis on the issue and make or suggest the necessary repairs or replacements.

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 is the right price to pay for the job

You have four different motor mounts on your 2004 Mazda3 and would need to have all of them checked and replace any that are broke. They range in prices and labors to replace them depending on the car. If you...

Q: Nissan 08 Altima won't start up when I press on the brake and push the start button.

Hi there. It sounds like the brake switch on the brake pedal is not working. There are two circuits on the brake switch, one for the brake lights and the other for the starter circuit. Some vehicles require the brakes...

Q: How many airbags does my vehicle have?

Your vehicle is equipped with six airbags, which can greatly reduce injury or save your life in the event of an accident. Your vehicle has two front-impact airbags, two seat-mounted side-impact airbags, and two roof-mounted curtain side-impact airbags. Tips 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 Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...