Hello,
I have an 03 E250 with the 4.2l v6 150k miles. She runs great most of the time unless I have been cruising on the highway for about 100 miles straight. With no real warning it will start choking and have no power. It will idle and continues to run but chokes when I hit the gas.
If I pull over and shut it off for a bit the problem seems to go away for a while. I have been working out of town for the past couple weeks and this problem has popped up several times so far.
One of the first times it happened the right rear converter was glowing hot. That one already was making a rattling noise so it got hollowed out and it has been running pretty smooth since. The plan is to replace the complete exhaust after Christmas.
Work that has been done recently: new filters(air and fuel), new coil, wires, plugs, intake bolts(helped cold idle a lot), and hollowed one converter.
Kinda leaning toward either the throttle or MAF sensor.
The only code that the ecu is putting out now is p0420 for the converter.

So the short version is is it runs well unless I have been cruising on the highway for about 100 miles. Then it falls on its face unless I shut it off for about 15 min then it is good for a while. Any help will be greatly appreciated.

Thanks