Hi.

I have a 2011 Hyundai sonata GLS with about 113k miles. It's making this rattling sound. Sometimes it may do it when you start vehicle very briefly. My check engine light have been coming on and going off on its own. The time it came on I had the thing at the part store put on it. I forgot the actual code but I do remember it was for the camshaft sensor. The check engine light has recent come back on again but I haven't check to see if the same code come up or something different. Last night I was out work which I have to drive a lot. I started about 4-430pm then about 830-9pm the rattling noise started. It'll make the noise continuously for a little while then stop for a moment then start again. I check my oil and it was low although no oil light came on  so I did put some in the car but it's still make sound. I was hoping you can help me to figure out what this noise could be. I've been going through a very difficult time financially and can't afford the run around and lies a lot of us run across out here when trying to get repairs done. Please help me figure this out if you can. Hopefully I gave enough details. If not I'm happy to give any additional info you need to help me figure this out. Thank you