Date registered: Jan 2006
Vehicle: 73 280SE 4.5, 71 300SEL, 03 BMW Z4, 72 Fiat 850, 80 Triumph TR7, 85 Porsche 911
Location: DC Area
Mentioned: 1 Post(s)
Quoted: 99 Post(s)
I had a similar issue with my 4.5. The fuel delivery system is very very similar.
Chasing down a different issue, I discovered I had some bad wiring (original wiring harness). I replaced it, and the car ran on all 8 cylinders, it always starts now, etc etc. I woud suspect you have an electrical issue. Trigger points might be the culprit, but I'd look more at wiring.
Once you pull the plugs, I suspect you find they are fouled in increments of two. The ignition system fires two cylinders at a time, so something common to both cylinders could be it (trigger points, wiring harness, cap or rotor). The raw gas out the tail pipe is a clear indication something's not firing correctly, as is the stalling at low speeds.
Keep a close watch on your oil. With so much unburnt fuel being pumped out the exhaust, it's highly likely you've ingested fuel into the oil, greatly thinning it out. Too much thinning out, and your engine siezes.
See the "online resources" portion of this forum - there are a lot of articles posted about the fuel delivery system that, if nothing else, would give you a greater understanding of how the system works.