There is a rattling noise while the car engine is on (idl...

Hi! My name is \*\*\*\*\* \*\*\*\*\* I will be able to assist you. I’m sorry that you’re having trouble with your vehicle. Don’t worry though, we’ll be able to figure this out. Please understand that I do not know your knowledge or capabilities so I may need to ask questions to find out basic information to help solve your specific problem. Sometimes it may take a moment for me to respond because I may have to look up information about your concern. I appreciate your patience and will provide responses as soon as possible. This could be caused by many things. It's most likely a problem with the lifters. Check the engine oil level to make sure it's full. You'll need to use a stethoscope to pinpoint the noise location on the engine. IF you can do that I can help determine exactly where it's coming from. Since it's only at idle, it's likely a lifter problem. My goal is to give you the best service possible and to help you. If you have any questions or concerns, please don’t hesitate to let me know. If I’m not online at the time, I will respond ASAP when I get back.

How do I resolve that issue then with the lifter?

You would need to check the oil pressure. If it's good then you'll need to replace the lifters.

How do I check that?

You'll need to install an auxiliary oil pressure gauge to the engine.