Ok I have a stupid question. I don't know much about cars, but a friend of mine is going to be bying a used 1997 eclipse GSX. Now when it idles it's fine but every 4 seconds or so it rumbles and sounds like its going to stall. I was wondering if this is normal or should he get it looked at?
Thanx for any help.

Edit: The sound is like when you let out the cluch on a standard with out giving it gas. It makes a rumbling noise, shakes and makes the same stalling noise, but before it stalls it starts to idle high again.

 

vacuum leak maybe? check the hoses.

 

IAC motor or FIAV... both commonly go bad on DSMs.