When I first start it it makes a pinging or tapping noise, I think we used to on 2001 Pontiac Firebird

call this noise tappet noise. It goes away usually after the engine warms up.

by in Melbourne, FL on February 12, 2012
2 answers
ANSWER by on February 12, 2012
The oil is too thick and needs changed.If it only does it when it's cold.
ANSWER by on February 13, 2012
Could be oil related. May have valve lifter that takes a while to pump up. But most likely it is an exhaust leak at the manifold. They can make a fairly heavy tapping/pinging noise cold. The manifold warms up & expands, thus the noise goes away.