1998 Honda Accord Popping noise under hood when initially a

Recently, I've noticed a popping or creaking sound coming from the engine compartment when I initially accelerate. After this initial popping sound I would stop the car and try to make it do it again while trying to figure out where it is coming from. It won't do it again unless I stop and put the car in reverse and accelerate. Again, it won't do it again unless I switch back to forward and accelerate. In an effort to isolate the location of the noise, I tested this further by stepping on the brake and giving the car a little gas while in forward. It would pop a couple of times initially but won't do it again unless I place it in reverse and repeat. Do you know what is making this popping or creaking noise that almost sounds like a piece of spring-loaded metal is hitting something hollow.