I have a 02 screw and I hear a noise when I'm using the throttle in my truck. When I am crusing I don't hear the noise. It sounds like a playing card in the spokes of a bicyle. I also have the dreadded 171 and 174 codes. I have changed everything you can think of associated with these codes. I have 169xxx on the truck. It sounds like an exhaust leak "tick" but it is comming from the top of the mainfold.

Any ideas?

 

Have you checked that rubber elbow on the back of the TB that goes to the pcv.....

 

yes already replaced-I've done MAF,air filter,PCV & hose & elbow at back of manifold, ox sensors,a couple of vaccum trees, EGR,DPFE and the EGR soliniod

the noise sounds like it is comming from the top of the intake