Q: Car engine sounds kind of loud and when I drive faster it gets louder. But the sound Will go away some times .

The noise could be exhaust related although there are other possibilities such as noisy bearings on engine accessories and pulleys. Exhaust systems can fail internally as baffles corrode over time. The poor engine running condition when cold could be caused by a stuck open, or poorly performing, engine thermostat, a fuel delivery issue such as inadequate enrichment on cold start, inadequate fuel pressure, clogged fuel filter, dirty fuel injectors, a malfunctioning idle air control valve and many other causes. I recommend you request an engine stalling diagnostic. The responding certified mechanic will get that issue resolved for you and at the same time will evaluate the noise complaint and let you know of the likely possible causes. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.