If your vehicle begins vibrating, shuddering, or jerking while driving, it’s usually a clear sign there’s a mechanical problem. However minor jerks felt during gear changes or when stopping can be perfectly normal.
As the owner of Moreleta Service Centre, serving Pretoria for almost 13 years, I want car owners to understand what causes abrupt jerking motions so you know when to be concerned. We’ll also explore some quick DIY checks and repairs you can make before resorting to the repair shop.
What Does the Jerking Motion Feel Like?
Jerking motions typically fall into two categories:
- Minor/Moderate: Brief vibrations or small jolts when accelerating, braking, or shifting gears. The irregular movement is short-lived.
- Severe: Sudden, forceful lurching motions that make it difficult to control the steering wheel. May be accompanied by loud clanking sounds from underneath the car. Often worst when accelerating but can occur anytime while driving.
Minor jerks and vibrations that doesn’t happen frequently, with no other symptoms are likely harmless. However, consistent, or violent motions indicate potentially serious issues needing a mechanic’s diagnosis.
What Causes My Car to Jerk?
Assuming you’ve ruled out environmental factors like bumpy roads, potholes, or strong winds, here are a few common mechanical and electrical faults that provoke jerky car motions:
Engine Misfires
When one or more engine cylinders fails to fire properly, it creates an imbalance in power delivery and turbulence that severely shakes the chassis. Causes include:
- Faulty spark plugs/wiring
- Clogged fuel injectors
- Vacuum leaks
- Failed ignition coils or compression
Severity: Moderate to severe, depending on number of misfiring cylinders
Loose or Damaged Motor Mounts
Motor mounts secured the heavy engine and transmission to the chassis. If mounts tear or detach, the powertrain will rock violently inside the engine bay during acceleration/braking.
Severity: Moderate
Faulty Transmission
The complex gears inside automatic and manual gearboxes synchronize to smoothly transfer engine torque to the wheels. When worn parts slip or get stuck during shifts, you’ll feel everything from small vibrations to sudden jerking. Issues include:
- Low transmission fluid
- Leaky seals and gaskets
- Broken gear teeth
- Faulty solenoids or clutches
Severity: Minor to severe depending on extent of wear
Traction Control Activation
Modern stability/traction systems detect and minimize tyre slip by strategically cutting engine power and applying brakes to wheels that loose grip. The pulsing motions keep the car balanced but feel jerky.
Severity: Minor
Loose Suspension Components
Worn tie rod ends, ball joints, control arm bushings, and struts allow more chassis movement over bumps. The unstable motion gets exaggerated at high speeds or quick maneuvers.
Severity: Moderate
Quick Checks and DIY Fixes
Before paying for diagnostic testing and repairs, try these simple checks:
- Electrical system: Rule out an ignition, fuel pump, or sensor failure by checking for warning lights, no start conditions, or stalling.
- Motor mounts: Look under the hood with the car running to spot excessive engine movement. Check that rubber mounts are intact and securely bolted.
- Fluids: Top up coolant, brake fluid, power steering fluid, and windshield washer fluid. Low levels indicate potential leaks reducing function.
- Tyres: Ensure tyres are properly inflated and have adequate tread depth (at least 1.6mm). Check wheel lug nuts are tight to specification.
- Filters/Fluids: Replace air filter, fuel filter, and old engine oil/transmission fluid. Use manufacturer-recommended types.
If symptoms persist after filters/fluids are fresh, it’s safest to have the vehicle inspected by one of our professional technicians. We’ll troubleshoot further based on your description of the jerking issue.
FAQs: Why is My Car Jerking?
Answers to our most frequently asked questions about jerky car motions:
Is it okay for my manual car to jerk when changing gears?
Mild engine braking and vibrations are expected on manual cars when shifting. Excessively jerky/noisy shifts could indicate issues like a worn clutch or damaged gears.
Can worn spark plugs cause my engine to misfire?
Yes, spark plugs wear out over time and begin missing firing cycles. This creates jerking, stuttering sensations. Replacing worn out spark plugs can sometimes resolve misfire issues.
What should I do if my car is jerking and stalling?
If your engine randomly cuts out or the car fully stalls, STOP driving immediately. This indicates loss of electrical power or fuel delivery putting you at risk of a crash. Call for roadside assistance and have the car towed to the shop for diagnosis.
Protect Your Investment Through Preventive Care
Like other complex mechanical systems, cars need regular inspections and fluid changes to achieve long-lasting operation. By following factory maintenance schedules, we can catch issues early before they leave you stranded on the side of the road or require pricey emergency repairs down the road.
As Pretoria’s original automotive experts since 2011, Moreleta Service Centre knows how to smoothly resolve even the most severe vehicle vibrations and jerking motions the first time. We also take test drives with customers to experience symptoms firsthand during diagnosis.
Don’t tolerate unpredictable car handling or noises that leave you tense behind the wheel. Our certified technicians are ready to thoroughly evaluate your car and discuss repair options if you’re experiencing any degree of jerking, hesitation, or loss of power. Book an inspection today.
