subari, hard starting, check engine light

I have a 95 Subaru impreza.

In the last 6 weeks the check engine light goes on and off. At cold
startup it is always on. With the key in the on position the system
runs the fan at all times cold or hot. When connecting the diag system
under the dash to get the the check engine flash codes it seems to be
pointing at almost every sensor in the car.

After the engine is up to operating temp it runs fine but, the check
engine light stays on.

It takes 20 to 40 attempts to get it running. Each time it will turn
over a few more time until if fumbles around enough to keep running,
then it smooths out and runs fine. No power loss, it seems to run fine
and then will restart fine. It seem as though the system can't tell the
engine temp at startup so it does not know how to manage the fuel. As
the engine warms up the temp gage seems to show valid readings.

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Question.

Is the temp sending unit used for the dash gage the same which is used
by the EMU?

Is there any particular sensor to replace to just do a test. I have two
of these cars so I can swap parts looking for the problem. As usual the
dealer will not tell me anything.