Hi All!

My friend has a 1984 380 SL with about 300K on the clock. A couple of years ago, it developed a problem of stalling for no apparent reason. It happens within a few minutes after start up or she can go 20 miles and it suddenly quits.
I replaced the ignition module and fuel pump relay, as I recall. It's been over a year since I last worked on it until recently, when I replaced the fuel filter. I replaced the two vacuum check valves and some cracked vacuum hoses. The oil temp sensor was loose and leaking oil, so I removed it and tested it in hot water and it worked fine. It's tight now, so it's got a good electrical connection to ground.
The idle is just fine, except for an occasional hiccup with the RPM dropping, then it clears up and runs fine for several minutes, then does it again sporadically.
The last time it stalled on her, it had sat for about 35 minutes at Costco, so she called me up to see if I could find the problem. The sparks were good and I got a few jolts there, but it wouldn't light up. Cracking a fuel line at an injector got some fuel weeping out when she cranked it. Then I was checking for power at the cold start valve (not knowing what it was at the time!) and there was no juice in Run position. When cranking, there was still no power to light up my test light, but then it fired up and ran all the way home just fine, except for those damn hiccups now and then!
Any ideas on what to look for or has this problem been solved before?

Thanks to all,
Randy