89 E250 Stalling while driving

My 89 e250 started stalling on the highway about 8 years ago. :frown: At first it would missfire and soon stall out but after sitting for 15 minutes would start and run all day like nothing was wrong. This only happened at first on a hot August day. Now I drive it about 15 minutes and it wants to stall at every stoplight, I need to throw it in neutral and run the brake and gas at the same time. Parts changed - both fuel pumps, gas tank, Distributor incl module, coil, EGR & EVP sensor, Dist cap & rotor, thermostat, plug wires, plugs changed regularly, wiper blades - lol:smooch: . Any ideas would be greatly appreciated.

What size engine do you have I think you may have a loose ground wire. This will trip the EEC IV relay and will shut down the engine. I will look up where it is located. Both the fuel pump relay and EEC IV relay and ignition switch will shut you down. I had a bad ground on a 85 T-B but it mostly caused a problem getting started. If you have somebody with you get out and put your finger on the EEC IV relay if you feel it click, next try the fuel pump relay.
This will narrow down the problem area. The fuel pump ground should be by the frame back by the tank.
I did a job for a friend and he brought me 3 bad new modules in a row. Did you use a quality module.
When I had a garage the Napa rep. went to a class and they cut them apart. Motorcraft,Napa-Echlin and Standard had all the parts. Some of the cheaper ones didn't. If I wouldn't have had my own tester I would still be working on it.

My motor is a 302. I have questioned the replacement module which was new but not done anything about it. Also the distrib I changed was a rebuilt one and I believe there is something in that which could possibly still be a problem. I was hoping to find something else which doesn't have the second guessing with it.

Auto Zone and Advance Auto offer free module testing if you take it in the store. I used a hair dryer and heated up the module as they fail when hot.
I put a drop of water on the metal and if it starts boiling stop. I've had them work perfectly and when hot fail completely.
For the distributor I use a 12 volt test light and put it on the coil negative. Slide it along the bracket until it touchs metal it should blink when trying to start. It acts like the old points opens and closes. If you don't have a test light unplug the distributor and use a DVOM and the ohms should go from zero to one.
A small wire goes to the battery for the ground. The other one should be along the engine near the relays. For the older vehicles it don't give exact but some Ford pickups I've worked on were in this area. The computer should be in the passenger side kick panel if I remember correctly. Check a ground close to the computer. The fuel pump relay is green and the EEC-IV is black or brown.

Actually, the last time it stalled on a hot day I had time to take the hood off inside the van, pull a plug wire and check for spark. There was a very hot and regular spark from the plug.

It appears to be a fuel problem feel the fuel pump relay and tell me if it clicks when trying to start. Also check along the frame for the fuel pump ground and clean it,coat with greese. Use a can of starting fluid and spray into the nozzle where the inlet air supply goes. If it starts right up you are certain its a fuel problem. Has the fuel filter been changed it should be along side the frame.
Pull the vacuum hose on the fuel pressure regulator if it has gas in it replace. Its located on the fuel rail going to the injectors.

Fuel filter is changed annually. I think I need a couple days now to play with the latest suggestions. Thank you VERY much.

I went exploring under my hood. After cleaning the mouse nest out from under the intake manifold I discovered a snapped vacuum line to, I believe, the MAF on the right side of engine . It has an insulated line up from the battleship on top of the engine and also a small vacuum line which came around the back of engine then forward and up to this. The broken line was inside some split loom cover which held it in place some of the time. I am thinking of changing all the plastic vacuum lines now. They are very brittle. Anyways it runs fine now but may stall next summer when the days warm up.

I used small rubber vavuum hose and slipped it over the plastic. It didn't leak and worked fine. You only need to push it on appx. 1 or 2 inches.

Thanks for the tip. I used some shrink tubing from my wiring kit and put 3 layers over the break. Seemed to work well too.