Hello. I have owned a 1991 3.1 Firebird for 8 years now. Until now I have found answers to all my questions by searching, mostly at this forum. Thanks!
Now I would like to hear your opinion about this engine noise, most noticeable at idle when engine is warm. Seems to come from bottom rear of engine. Hope this link works.

 

i have this on my 92 camaro, only noticable on idle goes away if u drive it or rev it up
my searches come back with timing chain.

iv replaced...
belt pully
Power steering pump
water pump
alt
removed the smog pump (dont need emissions where i live)
AC is brand new.


grab a screw driver or a hose put it up to where you THINK the noise is coming from
put your ear on it see if u can locate it (use LONG screw driver) and be carefull

another post i seen that plate the starter turns (flywheel) was broken in his car that made that same noise too