strange growl

I have a 94 t bird w/3.8 that idles a little rough, has a lack of power, and makes a strange growl sound around 30 mph when it makes that sound it looses power until you accelerate more, than clears up , could it be an obstruction in exhaust?

Try increasing engine rpm's while in Park to see if you can hear the growling sound. If it does make the sound you should be able to find out where it's coming from. Just don't over rev the engine when you try this!

thanks, it does`nt do it in park or in gear while holding the brake, only while I`m driving, it`s actually been doing it for years and has`nt gotten any worse