I have 07 justa hits 68k miles. I used to have problem with rpm idling but mechanic says it doesn't look bad so i didn't care that much but today I was heading to work and when I full stopped on stop sign and I noticed that I hear engine rattling from hood and rpm goes down to 500 and up to normal.. car was kinda shaking.. do you guys know what the problem is?
please help me out!!!! thanks

 

Check engine light (CEL) present?
Scanned the car for any fault codes (regardless if there's a CEL or not)?

Have you done any preventative maintenance including plugs, timing chain tensioner, etc?

- Erik

 

scanned the car last time when I went to service but nothing came out.
I haven't done plugs,,timing chain either.. do you know how much they will cost?

 

You shouldn't need to change a timing chain. You probably have a gummed up ICV or a vacuum leak.