How to fix cold starting problem?

fix/adjust the automatic choke setting

Having to spray starter fluid is an indication of lack of fuel. Possible restricted fuel filter or fuel pump getting bad. If the problem occurs in the AM when vehicle is cold and is started for the first time, there may be an issue with the coolant temp sensor providing inaccurate information to the computer. Have the computer scanned and monitor operating parameters of the sensors to help isolate the cause of the problem

I would say that the choke sensor (or whatever it is called) went bad & isn't telling the computer that it's cold & requires more fuel. Instead of starter fluid, did you try to push the foot feed 1 or 2 times?

That's extremely vague but I would start with checking your fuel supply. Is gas coming in?I.e.fuel filter or injectors. Then if that cleats check for obvious vacuum leaks.

1. Do not use starter fluid on a glow plug diesel engine. (explosive)
2. Most likely 1 or more of your glow plugs is out. They are not too expensive and are fairly easy to change. Facing the engine, look on the right side. There is a set of "plugs" with hoses, and a set of "plugs" with wires. You want to change the set of plugs with wires.

you say it will start right up if you spray starter fluid this should tell you something, the starter fluid takes the place of fuel(gas). the fuel is not getting to the cylinders when the temp gets cold. have the fuel pressure tested with a gauge to make sure its within spec.

How aboput the fuel pump relay, does it have power to at least two of the terminals with the ignition key in the crank position?

I would check the compression. As air compresses it heats up. A trick I've used on cold diesels is to bump the starter trying not to let the motor actually turn over, so you keep compressing the same air. Do that a few times then try starting.

Remove the transmission & see if the front pump seal is worn,
where the torque converter goes in

check fuel filter first then check fuel pump