Popping Noise again, not A/C as suspected

["Alexander van Gerbig" <Audi_80@email.msn.com>]

    Got a loud popping noise from the engine this morning when cold.  It
wasn't a constant noise it sort of came and went with the idle.  It didn't
seem to come from the A/C this time, same noise different spot.  Now it
seems more like the exhaust manifold, scares me.  This could be a small
crack in the exhaust manifold?  As the engine warmed up the noise got
fainter and fainter, then dissapeared.  Used a screw driver and put it to
the manifold with my ear against the handle, did seem like it was from
there, but not sure what it is?
    What could be making a popping noise from the passenger's side of the
engine bay?

Thanks!

Alexander van Gerbig
'88 Audi 80 -- Koni Yellows, G&M Springs
HÖR Technologies Sport Hydro Cam, K&N Filter
Borbet Type T, Dunlop SP9000 Sport

The Audi 80 Pages------------------
http://surf.to/the80pages.com

German Parts Importing------------
(914)-232-7467

Katonah, NY 10536