Mine was making some hell of a noise as well. I so far fixed it by ensuring EVERY possible leak spot past the MAF was tight/in working order. I put on a clamp to the one pcv valve and a new hoseclamp on my intake. Also a new gasket on my EGR (only cost 2 dollars and 10 minutes). Also had to buy a new IAC and gasket. Also finally gave in and picked up a code reader! So i'm probably around 120 bucks.
i but i paid 75 for the reader and 38 for the IAC.
