Q: vibration and shaking at idle. also very loud and noisy engine. replaced all motor mounts, spark plug components, and intake syste

asked by on October 05, 2017

I noticed that ever since I bought my car it shake at a red light or stop sight until I hit the gas. It is also accompanied by a very loud noisy that persists when I accelerate. when at idle its a pulsating noise sounds like a pulley. I have replaces all motor and trans mounts. also all spark plugs, wires, and ignition coil pack. the timing belt has been replaces as well as water pump. idle air control valve and throttle body has been replaced. no blown head gasket or leak. have replaced all vacuum hosed and PVC valve. the king is worse when idling as well as the noise from the engine along side some ticking noise.

My car has 139000 miles.
My car has an automatic transmission.

Car idle is rough Inspection $79.99 - $99.99 Get a Quote

Often noise is related to exhaust system leaks or internal failures in the exhaust such as loose baffles in the muffler. To rule out accessory drives and pulleys as a source of noise what you can do is momentarily run the engine without the serpentine belt attached. That will help you distinguish between "internal" engine noise versus noise from "external" accessories such as a pulley, alternator, etc. The rough idle and vibration could be due to anything from sticking valves and uneven compression (all mechanical problems) to a bad tank of gasoline, dirty fuel injectors, incorrect idle speed, exhaust restrictions, vacuum leaks, incorrectly installed or damaged spark plugs, a defective or clogged fuel pump or fuel filter, failing electrical components such as the ignition control module, plug wires, coils, and spark plugs, a defective airflow sensor, dirty oxygen sensors and other causes. I would recommend that you request a rough operation/rough idle diagnostic and the responding certified mechanic will perform the required diagnostic steps to get all the issues (noise, rough operation, etc.) resolved. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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