My 99 F250 Super Duty will not respond to the accelerator. It was fine when I shut it off last night. It will idle and move forward and reverse, but will not accelerate.

If it is an automatic which I assume it sounds as if the servo engaging the band inside the transmission has failed. Did it go all at once? Any odor of burning fluid?

linkige might be goiing out takes about 30 bucks at autozone for parts if you know how to put it on

10 amp fuse labeled instrument cluster also protects idle sensor on diesel models

Have you checked your fuel pump? Or the filter, I had a 04 , where the filter would clog and make it run bad, i would shut it off and the pressure would release and move whatever was there, I would then run fine for a while and repeat again. I changed the filter and it was fine. I also had a chevy with a bad fuel pump that would work great most of the time but not so great other times? Replaced it and solved the problem!

clean throttle body

I hate to say it but it sounds like you have a severe problem in the rear end. Here are a couple of things i would do. First pull off your tires and wheels. Of course you need to put the truck on jack stands and block the wheels for safety! Disconnect your rear drive line so you know nothing from front diff or trans could be affecting it. Next spin the brake rotors by hand and inspect them for severe damage. Go forwards and backwards. Also listen in your rear end for grinding or clunking noises and also excessive play front foward to reverse. And last drain your oil and put your finger up inside the housing as far as you can and feel for large pieces that should not be there. This should give you a good idea if it is in your braking sytem your rear end or wether you need to start looking at front diff. or the trans. If all is good on rear end do the same thing for front diff and inspect it as well. Make sure you pull front driveline off!

I bet you also lose the function of your cruise control when it happens. I would start first with checking the wiring connection on the vehicle speed sensor (also acts as abs sensor). Remove the sensor, clean it up and reinstall. If that doesn't work, replace the VSS.

You will find it on the top of your rear differential.

Side note: If you ever get stuck in the mud/snow and have to rock the truck forward/reverse, sometimes that will trigger your ABS light as well. This will normally reset itself after a few on/off cycles of the engine.

Some of the Ford transmissions actually have an aluminum gear which will go out somewhere around 150 to 200 thousand miles. OR it could be really low on transmission fluid.

she's pooched, your forward gears in an automatic are completely separated from the reverse same with a standard either way your on your way to the tranny shop

idle air control valve or
idle air control motor is possible

same thing but diff parts stores call it diff name