Idle & Combustion - Noises & Vibration Symptoms
Common symptoms and diagnostic guides.
Car vibrates then smooth in town traffic
This symptom typically indicates rough idle due to engine or fuel system issues, engine mount wear, or ignition problems that smooth out once moving or load changes. Investigate fuel, ignition, and mount components.
Engine feels unstable on concrete
Engine instability or vibration when idling on concrete is typically due to rough idle caused by ignition, fuel, or intake issues leading to uneven combustion and engine vibration.