Truck dieing problems
 

Ok so my truck only dies / bogs down like its about to die when I'm getting on it hard.. ( pretty much redlining ) when I'm mudding, burning out ect. This only happens when I have it in D (drive ) but when I lock it in to the gear 1 or 2 I have no problems at all and my truck runs great and dosent want to die. I have replaced the cam shaft sensor 2wice and the current one is motorcraft. Any ideas or sugesttions what causes this? Thanks !