A car that shakes when accelerating usually has a problem that only shows up under load: an engine misfire, worn engine or transmission mounts, a worn inner CV joint or driveshaft U-joint, or torque converter shudder. Shaking that appears only at a certain road speed, whether you are accelerating or not, is more often a tire, wheel or balance problem.
Match the shake to the cause
| When it shakes | Likely causes |
|---|---|
| Accelerating but not when coasting | Inner CV joints, mounts, misfire under load, U-joints |
| From a stop | Engine or transmission mounts, CV joints, torque converter |
| At 40 to 70 mph regardless of throttle | Tire balance, bent wheel, out-of-round or separated tire |
| Light shudder at steady 30 to 50 mph, like rumble strips | Torque converter clutch shudder; see torque converter shudder |
| Accelerating and at idle, with a check engine light | Misfire; see engine misfire and P0300 |
| Uphill or under heavy load | Misfire from weak coils or plugs, mounts, transmission slip |
Misfires
A cylinder that misfires only under load is a classic cause, and the check engine light may flash. Worn plugs and failing coils are the most common reasons; see spark plug symptoms, ignition coil symptoms and check engine light flashing.
Mounts
Engine and transmission mounts let the engine rock when torque is applied. A broken mount causes a clunk or a heavy shake when pulling away and when shifting between drive and reverse; see engine mount symptoms.
CV joints and driveshafts
On front-wheel-drive cars, a worn inner CV joint shakes under acceleration and goes quiet when coasting; a worn outer joint clicks when turning. On rear-wheel-drive trucks, worn U-joints or a driveshaft out of balance cause vibration that grows with speed and load.
Tires and wheels
A thrown balance weight, a bent wheel or a tire with a shifted belt causes shaking at a particular speed range. Have the tires balanced and inspected before replacing drivetrain parts; see car vibrates at high speed.
How to narrow it down
- Scan for codes; see how to use an OBD2 scanner.
- Note whether the shake follows road speed, engine speed or throttle.
- Shift to neutral while coasting: if the shake stops, it is load-related (engine, mounts, axles).
- Inspect mounts and CV boots for tears and grease.
When it is the engine or transmission
If the cause is internal damage, such as low compression or a failing torque converter, compare repair with replacement; see car jerks when accelerating, our engines and our transmissions.
More guides: wheel bearing noise · bad CV axle symptoms · U-joint symptoms.
Trouble codes: P0741 Torque Converter Clutch Stuck Off · all OBD2 codes.
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