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

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.