I have a 1999 7.3 F-550 that at a stop just turns off. It always starts right back up and you never know when its gonna do it. It will even die while I'm slowing to back in somewhere or pulling in somewhere. Ever try and steer something that ways 15,000 with no powerstrearing? lol It's not every day but it happens at least a few times a week now. Today it started to turn off while going down the highway but due to me doing 60 never died completely. It only felt like a sneeze, did that a few times on the highway then after about 30min didn't do it anymore.

It started about 3 weeks ago and only happened once that week but it has gotten worse with the passing weeks and days, today being the worst.

Any ideas as to what may be going on or things to try?

 

I'd start with the cam position sensor. Do a search. Lots of info.

 

Mine did the exact same thing, it wound come and go. It did it for the PO for a year. I got the tip here! It was my fuel bowl heater. Try unplugging the electrical plug on the drivers rear of the fuel bowl, and leave it unpluged for now and see if the problem stops. It doesn't hurt to leave it unpluged for now. It also could be the cps on the front of the motor. It's easy and free to try the fuel bowl heater first.

 

The CPS, Fuel Bowl Heater, IPR, and a wire harness chaffing can cause that.

The IPR should be looked at. Check the tin nut on it to make sure it is tight.

Also check the chip if you have one. They work loose and can kill the motor.

The wire harness along the heads and where it crosses to the valve cover are often high chafe areas. With the truck running, start wiggling the wires. If it cuts out, you may have found your issue.

 

I had the same symptoms a year ago. it finally died and wouldn't restart after about a month of playing with it. it ended up being the IDM.
Tried checking codes yet?
Hope this helps and good luck!