I've got a 1990 e-350 460 7.5l cargo van. Practically bulletproof. Lately It's been giving me this problem. This problem started small, but over time it gets worse. I'll be driving on the road, or in idle, it doesnt matter, when Everything stalls! I lose all power, electrical, engine... Everything! Sometimes it will pick itself back up in about 2-5 seconds. But lately it dies, and takes anywhere from 5-10 minutes to cool down before it will start again. Another thing is after she stalls and Im waiting to cool down, I get my electrical back, but sometimes the blinkers and hazard lights don't work, and I have to bank on the side the steering column to get them to kick on. Sometimes when Im on the road and she is about to stall, I bang on the steering column with my fist and she'll kick back on... I don't know if this is just coincidence or not, as it doesnt work every time. It always starts fine when I first crank her on, but after she gets hot (she runs hot anyway) thats when I get the problem. I have eliminated the alternator and battery. I have a feeling its the TFI/ICM, but before I replace that, I want to rule out the Ignition Coil. Also when I opened up the engine, I noticed one vacuum wire that completely lost connection... Any thoughts? I just replaced the Fuel Pump and Filter, spark plugs recently. I know I'm getting gas, because it will do this at night when it's 60 degrees outside (California)... Any Thoughts?

 

If you are banging on the steering column, I would suspect the ignition switch is part of your problem. If it's like the trucks(I have never worked on a van) it will be mounted on top of the column, under the dash. A good way to get to it in a truck is to loosen the u-bolt that holds the column to the dash and drop the column down.

 

Here's a link. It looks like yours is like the truck switches.
| Repair Guides | Steering | Ignition Switch | AutoZone.com

 

I have a suspicion that the ignition switch and the coil and/or TFI module are both suspect.