Skip the auto shop - Our mechanics make house calls

Q: Car starts bucking/jerking when letting off gas on the highway

asked by on

This started not too long ago, it only occurs at high speeds. I noticed it occurs after 60mph. When i push the gas peddle, it drives fine, it doesn't jerk or anything. But when i let go of the gas, the car has a sudden jerk as if its gonna turn off or something. I would think its a motor mount, but then this problem doesn't occur in the city, only on the highway at higher speeds. I changed the transmission fluid, the transmission shifts fine. My car doesn't have over-drive. Its a 2006 suzuki forenza 2.0. And i dont have check engine light. Although when i did the motor mount test. The motor moves forward about 2 inches in reverse with the brake peddle held and gas pushed to 2000 rpm. and i checker the sparks and the wires and the coil pack, they seemed fine, i replaced them 6 months ago, and it is oem spark plug. Im thinking fuel injectors?although i checked them and they tick just fine. please help me

A: This is very likely a throttle issue. There...

This is very likely a throttle issue. There is an idle control module (or similar setup depending on your make and model) that is located on the throttle body which helps the gas regulation during these moments. Otherwise, without a regulator, the car performs much like you are describing. There are several sensors, wiring harnesses, and the module itself that can fail. It is likely a code scan will detect some of these issues. Start by having the vehicle scanned for diagnostic troubleshooting codes. If this doesn’t give you any information, then you should look into replacing the idle control module.

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

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: Charge warning light. Ran over extension ladder on interstate.

Hi there, thanks for writing in. I'd be happy to help. I'd recommend to first see if the issue lies elsewhere before replacing the alternator, in case it doesn't need to be replaced. It sounds like the collision with the...

Q: Car wont start but cranks 1998 Nissan Altima

Hey there, thanks for writing in about your 1998 Altima. You may have a crankshaft or camshaft sensor causing the no start. You can scan the computer and watch the data to see if one or both of these sensors...

Q: Vehicle sputtering

You most likely have an engine misfire. The cause could be an ignition coil, spark plug, or plug boot problem, such as the valve cover leaking oil into the spark plug hole, shorting the coil out. I recommend that you...

Related articles

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
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...