Ok I've been checking all the email but I still can't figure out what it's going on. It does not matter if the truck is cold or hot been on for 5 min or 2 hours, every time I press the accelerator my 99 f150 whines! What's the deal! Replaced a cracked exhaust manifold, bank 1 02 sensor, sparks&cables. I'm lost plz someone help

 

Is it the rear end that's whining? If so, go get your differential gears fixed. Otherwise the pinion will slip out at some point and good bye rear axle.

 

Have you checked your alternator?