1990 Mitsubishi Van

Engine Performance problem
1990 Mitsubishi Van 4 cyl Two Wheel Drive Automatic 78000 miles

Hi, I bought a 1990 Mitsubishi van recently.
Here is a quick history - Upon buying it, I needed to and have replaced the fuel pump, filter, seal the fuel tank, timing belt and water pump and gave new cap plugs wires and rotor. Since then (400 miles) it was working great till a few days ago when it stalled on the highway. I got it restarted a few seconds later by shutting off the ignition then restarting- I could drive for about 30 more seconds and it stalled again -

The next day I drove it and it worked fine for about 10 minutes where it began to stall again - after 10-15 minutes of multiple stalls it ran perfectly again for the next 40 minutes to work and the ride home.
I checked the cap and wires and looked for a loose anything that would make it stall but no such luck. Ran it in idle for about an hour and no stalls - but driving it - it stalled. I am wondering what to look for next - fuel pressure (with a t or some fuel rail adapter?)? Vacuum leak?

thanks for any help
August 27, 2010.

I am wondering if you ever found the problem? I have the symptoms
I thought maybe a coilpack? Or catalytic converter?

Feb 12, 2011.