1986 Other Volvo Models

Hi I have a Volvo 360 GLT. This has the 2L B200E engine in it which is also found in volvo 740 and 940's.

I was driving along around 50kph when suddenly the revs rose to about 5000rpm and stayed there. I quickly turned the engine off as I didnt know what was happening. Afterwards I tried to restart the engine but it just kept cranking over but wasnt igniting.

After getting it back home I started to try to diagnose what was wrong with it. Here is a list of what ive done:
-Checked Fuses. All ok
-Check Leads. All ok
-Check Spark. Initially there was no spark coming from the ignition coil, the coil was taken out and terminal cleaned. This enabled a spark to come from the coil. Afterwards, there was no spark from the distributor. Once again I cleaned the terminals on the distributor cap and this gave me a spark. The spark isnt a pure blue as expected but rather a bit more yellow. None the less there was spark. Still no start.
-Check fuel. Full tank of fuel and can smell plenty of fuel coming into the cylinders with a plugs off and also can smell it with them on so I assume there is plenty of fuel.
-Check Injectors. Used niod light and theyre ok.

A friend suggested that the vacuum advance is the problem, how am I able to do diagnostics on this?

Also, if I leave the motor for a while and try to start it you can hear one cylinder fire once when u crank it but nothing more after that, only cranking.

Just about all out of ideas. Any one have any clues?