I believe I had the same problem recently. I have a 1990 Winnebago Warrior based on an E350 with a 460 engine.
Took the RV up to Virginia back in May. Was having overheating problems. Got home and started to drain the coolant to replace the thermostat, and noticed looking down the filler neck that the radiator was full of sediment encrusted around the cores. You can read my entire radiator replacement saga here, with pictures. For those not interested in going to the link, don't buy from CarID.
https://www.ford-trucks.com/forums/1543596-suggest-a-radiator.html
Here is a shot looking down the filler neck:
When I got the radiator out, it looked even worse on the bottom end of the cores.
Anyway, I got the radiator and thermostat replaced, and went for a test drive. It was about 100F out and I ran for about 20 minutes at 65 MPH, then down the interstate at 70 MPH for about 15 minutes, and then got off onto a surface street to come home. I had the AC on Max the whole time.
As soon as I got off the interstate onto a surface street, the engine started misfiring/backfiring in the intake whenever the accelerator was pressed. The RV was stumbling to death and I was just able to pull it into the center turn lane of this 5 lane road I was on when it died. Attempts to get it to start again resulted in a fast crank-over with misses on cranking that made it sound like it was out of gas. I called Good Sam for a tow, but while they were off looking for someone (this was the 4th of July) I popped the hood and noticed that the negative battery terminal connection was loose. I had pulled the battery during the radiator install, and my battery cut-off switch had broken, so I hastily replaced it with another bolt-on terminal I had in a toolbox. Evidently I did not tighten it enough. I used my tools to tighten the connection. Tried to start, but it did the same missing thing. After waiting about 15 minutes, it started back up again and drove home without issue, so I was able to wave off Good Sam before they sent anyone.
Like you, I got no codes. But, the bad battery connection may have wiped them.
My hope is that with the negative connection disconnecting from the battery that it just sent the ECM into a tizzy.
But, people over on the E350 forum (see link above) were saying that it is not uncommon for the PIP sensor to go bad. The PIP is the profile ignition pickup (pip) sensor, otherwise known as a camshaft position sensor. Unfortunately, this sensor is inside the distributor, and it's generally easier to replace the entire distributor rather than disassemble it and replace it.
Other suspects are the Engine Control Computer, or the Ignition Control Module, but it was said that they do not go bad as often as they are located on the fenders and away from the worst of the heat.
Steve
