High idle speed and then not starting

[sprdad]

I have 1991 fuel injected TB 42 which has recently started to have erratic idle speed. The first time it idled around 1200 RPM but only for a short time them went back to normal running. Ran fine for a couple of weeks until this morning, when it again would not drop idle below approx 1200 RPM after it warmed up. I turned the engine off and when I went to start the engine again it was a no go. It acted as if there was no spark, plenty of battery power it is brand new. I pulled the lead on the number one cylinder to check for spark and with the first turn of the key the engine started and ran at normal idle. This could have been coincidence or a clue? I have also noticed that turning the heater fan on affects the idle speed slightly.
All ideas greatly accepted.

Have just replaced the distributor cap, rotor, plugs and leads. Also replaced all of the vacuum hoses.
The vehicle is certainly running a lot better and so far has not died and then not started again. However there is still an issue with the idle speed fluctuating while sitting in park. It seems to me that it might be one of the electronic vacuum control sensors or maybe the sensor that controls the idle and air mix for the cold start in the morning.
If anyone has any ideas about which module might be the culprit I am all ears.