Symptoms / Car shakes or vibrates when accelerating
Car shakes or vibrates when accelerating
Get it checked soonVibration that appears under acceleration and fades when you lift off usually points to a misfire under load, a broken engine mount, or a worn axle joint.
What this usually means
The useful clue here is that the shake is tied to the throttle, not to road speed. Vibration that shows up when you accelerate and eases when you lift off comes from something that only acts up under engine load: a cylinder that misfires when cylinder pressures rise, an engine mount that lets the drivetrain twist and buzz against the body, or a worn inner CV joint that vibrates when torque flows through it. That makes it a different problem from a shake that tracks with speed regardless of throttle (usually tires or wheels) or one that appears only when braking (usually rotors) — worth being clear about before anyone starts replacing parts.
Most likely causes
- highMisfire under loadA weak coil, worn plug, or lazy injector may fire fine at cruise but drop out when you accelerate, and a skipping cylinder shakes the whole car.
- highBroken or collapsed engine/transmission mountMounts hold the drivetrain still as it twists under torque. A torn mount lets the engine rock into the body under acceleration — often with a clunk when you shift between drive and reverse.
- mediumWorn inner CV jointInner joints on front-wheel-drive axles vibrate specifically under power, typically felt as a shudder through the floor during acceleration that disappears when coasting.
- mediumBent axle or worn driveshaft componentsOn rear- and all-wheel-drive cars, a worn U-joint or unbalanced driveshaft vibrates under torque, often getting worse with speed.
- lowTorque converter shudderOn automatics, a converter clutch that grips unevenly causes a brief rumble-strip shudder at light throttle around 40–50 mph, sometimes cured by a fluid service.
Is it safe to drive?
Typical fix & cost
The pattern sorts it quickly: a scan reveals misfire codes; a shop can watch the engine rock under power brake to spot a bad mount; a torn CV boot flags a joint that’s been running dry. Fixes range from plugs and a coil, to a mount, to a replacement axle — all moderate jobs. Converter shudder is often addressed with a fluid change before anything bigger.
Typical range: $100–$1,200
Ignition parts or a single mount are the low-to-middle range; an axle or driveshaft repair is the high end.
The price depends on which cause it turns out to be — so confirm the cause before paying. Diagnose this for my exact vehicle →
Frequently asked
How do I tell if it’s the engine or something in the drivetrain?
Try a gentle rev in park or neutral. If the shake appears without the car moving, it’s engine-side — a misfire or a mount. If it only shows up under power while actually driving, suspect an axle, driveshaft, or converter.
Can a bad engine mount really shake the whole car?
Yes. The mount’s job is to absorb the engine’s torque reaction; when the rubber tears or collapses, that movement transmits straight into the body as vibration, and often a thud when shifting into gear.
Seeing this on your car? Get a diagnosis specific to your exact year, make and model — RedlineAi ranks the likely causes against real recall and complaint data, with an honest confidence score.
Diagnose my vehicle →Related OBD-II codes
If your car has stored a trouble code, these often accompany this symptom:
Related symptoms
This is general guidance, not a substitute for a hands-on inspection. Cost ranges are broad estimates to set expectations, not quotes. For safety-related issues, have the car inspected by a licensed mechanic before driving.