Volvo: 760 starting problem, vacuum system, control fuel

Question
(Here's hoping you something about the PRV v-6!)

I have an '83 760 with the b28 engine.  It starts okay when cold, but it needs to run for approximately 1 minute before you can accelerate, otherwise it almost stalls.  Any ideas?

Answer
It sounds like a fuel problem, as if it is running to rich while cold.  Could possibly the cold start valve.  Another issue to look at is how the vacuum system is doing.  There are several lines between the distributor and injection manifold that control fuel to timing.  Issues with that can affect cold running drastically, but usually have other more minor symtoms once the engine is warm.