Tapping noise from motor of vr wagon

[joshii]

Hey guys I just can't win with this car lol i don't think anything else could possibly go wrong after this here's the issue...

My exhaust is leaking from the flanges after the o2 sensor only slightly however the cars engine light comes on at around 1500 rpm only when there is no load on the engine as in, in between gear changes or under very light throttle. There is also a loud tapping sound that comes from the motor around the same rpm. I have checked the fault codes which have told me there's a leak in the exhaust and the car is running lean. My question is can a leaking manifold gasket cause this Loud tapping sound and possibly be sucking air into the exhaust causing it to give me a lean fault code? Also the noise gets louder as the revs go up but only on very minimal throttle the noise goes away if you
Put your foot down and put the motor under load the motor also surges and idles quite rough it has a stage 3 crow cam in it but I wouldn't think it would cause any of the above issues? Any ideas?

[Brett_jjj]

An exhaust leak near the engine,or exhaust manifold leak can sometimes sound like theres a tapping sound coming from the engine..

[VR_Acclaim]

I would say the cam has worn out the lifter

[pjdm1980]

The exhaust leak will definatly give a o2 sensor a faulty reading making the engine run rich, and the noise could be anything from the exhaust, lifter, cam and bottom end, but I'd start with the cheap one and fix the exhaust and work your way from there.