Sometimes when you push down on the accelerator nothing happens?

Sometimes when you push down on the accelerator nothing happens. There is no change in the RPMs, If I continue to press down the pedal and release it 5/6 times all of sudden it starts working Again like nothing ever happened. Just the other day the Engine Light came on, I've haven't had time to scan it yet knowing I have more than one rig to use. I'm thinking that it may be time to replace the Accelerator Pedal or the CAT other than this issue, the truck runs great... thanks for any idea or thoughts on this issue. PS. it's a turbo diesel.