Make a Mobile game not lag after time

I've had this problem for every game I've done on the iOS.

I've checked to make sure that I'm deleting all the objects I create when not needed, and there's always been around 10-30 objects on the screen. At the start it's fine, but after around 2-3mins it starts lagging.

This is very problematic since I'm doing an endless running game.. would appreciate any help I can get! Is there any sort of memory leak or something that I could be missing besides deleting objects?

EDIT: This is the same on both Mobile web and CocoonJS when hardware accelerated..

I'm pretty sure it was battery problem

I've made a game for iPod touch 4, i've noticed it starts lagging after some mins.

Otherwise, i connect iPod 4 for battery and play, it never lags after of 10 mins

Weird, my game solved it's own problem. o_O

May have been something to do with sound or maybe deleting objects.

But thanks anyway Joanne! I tried it, there is a slight different on my iPhone 5 as well.