My car has been making kinda popping noises out the exhaust when I rev it up and the engine is cold. My dad says not to worry about it cuz "it's just a normal backfire" but it doesn't sound normal to me, especially for an engine w/ only 43,000 miles... any ideas as to how to fix this?

 

does it pop while the RPM's raise? lower? thus far it could be an exaust leak, you could be leaning out.

 

while the rpm's are dropping...