High-Probability Causes:
* Transmission Problems: This is a very common cause of jerking during acceleration. Possible issues include:
* Low Transmission Fluid: Check your transmission fluid level and condition. If it's low, dark, burnt, or smells bad, you likely need a fluid change or more serious transmission repair.
* Failing Transmission Solenoid(s): These control the flow of fluid within the transmission. A faulty solenoid can cause erratic shifting and jerking.
* Worn Clutch Packs or Bands: These components wear out over time and can cause slipping and jerking. This is a more serious and expensive repair.
* Torque Converter Issues: The torque converter can fail, causing slippage and jerking.
* Spark Plugs and Wires: Worn, fouled, or damaged spark plugs and ignition wires can cause misfires, resulting in a jerky acceleration. This is a relatively inexpensive and easy fix.
* Fuel System Problems:
* Fuel Filter Clogged: A clogged fuel filter restricts fuel flow to the engine, leading to hesitation and jerking.
* Fuel Injectors: Clogged or failing fuel injectors can cause inconsistent fuel delivery.
* Fuel Pump: A weak or failing fuel pump may not provide sufficient fuel pressure.
* Mass Airflow Sensor (MAF) or Throttle Position Sensor (TPS): These sensors monitor air and throttle position, respectively. A faulty sensor can provide incorrect information to the engine's computer, leading to poor performance and jerking.
Less-Likely (but still possible) Causes:
* Oxygen Sensor (O2 Sensor): A faulty O2 sensor can affect the air/fuel mixture, contributing to jerking.
* Computer (ECM) Problems: While less common, a malfunctioning engine control module can cause various driveability issues.
* Engine Mounts: Worn engine mounts can allow the engine to move excessively, leading to vibrations that feel like jerking.
What to do:
1. Check the obvious: Start with the easiest and cheapest checks: transmission fluid level and condition, spark plugs and wires (look for wear, cracks, or fouling). Also, inspect the air filter – a dirty filter can restrict airflow.
2. Get it scanned: Take your car to an auto parts store (like AutoZone, Advance Auto Parts, etc.) and ask them to perform a free OBD-II scan. This will retrieve any diagnostic trouble codes (DTCs) stored in the car's computer. These codes can provide valuable clues about the problem.
3. Consult a mechanic: Based on the results of your checks and the OBD-II scan, you may need to consult a qualified mechanic for diagnosis and repair. The transmission is a complex system, and improper repair can lead to further damage. Don't attempt major repairs yourself unless you have significant mechanical experience.
The jerking during acceleration is a serious issue that shouldn't be ignored. Continuing to drive the car could cause further damage. Get it checked out as soon as possible.
