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Problem Engine wont start when warm. HELP!
Starts when cold, runs great, after turning off, starts again after a few seconds, after a few minutes, it
wont start. Cranks OK. Starts again after cooling down. When it does not start, I can get it to start
using "Starting Spray" Got to throttle a little until it stabilizes.
New spark plugs and wires, new coils, good spark, compression, new coolant temp. sensor, throttle position
sensor, cleaned Mas Air Flow sensor & Throttle body. Running out of ideas - Help!!!

Sounds like a crank position sensor.

OK, I've got an 01 Buick Regal 3.8 that has a similar problem. Starts great cold, once it's warm if I shut it off it starts hard but will start eventually not using any starting fluid. It will start and die right away. Maybe after 4 or 5 attempts it will almost die but then decide to keep running. That's if I don't give it a little juice the 1st time to keeping running.
Replaced the MAF and cleaned the IAC.
Leaning towards the CPS as well given it seems to shift hard as well but was hoping I could be more positive in my diagnosis before throwing money at it.
Great car otherwise. Lot of new parts including brand new tires, brakes, rotors, bearings, tie rod ends on a car with no rust or dents, good clean leather interior that I paid $1200 for.
Is there any way to test this that I don't know of? It had old codes I cleared and the cel hasn't come back on so far.

Problem solved. I decided to just take a shot and bought the CPS. I was looking it over getting my plan of attack down and almost as an after thought decided to pull the vacuum line from the fuel pressure regulator and smell for a distinct odor of gas which no question there was. Upon lowering that end of the line gas actually ran out of it. Not a lot, but any gas getting into that line is a sure sign the regulator is bad and a possible cause of my symptoms.

I'd be inclined to suggest the OP here check the vacuum line for any sign of gas or distinct odor suggesting gas is/has been present in it. The fact your car starts/runs when using starting fluid, my money is on the FPR being your problem as well. Easy enough and worth investigating before tackling the CPS.

Make sure you check/change your oil and spark plugs etc. should this be your problem as it allows gas into areas you don't want it.
Simple fix tho and the regulator costs approximately $50. Took me 2 minutes to change. Car runs smooth and starts everytime as soon as the key is turned.
Also, my old one came out in pieces so make sure you get everything out including the small oring or the new one won't install properly.
If it installs in the front fuel rail like mine does, all you need is a snap ring pliers to remove a snap ring.

Well, while the FPR was obviously bad, it hasn't totally solved my issue either.
However, something I noticed was the coolant fans aren't coming on either and that leads me to believe the coolant temp sensor may be the problem as it's basically the master sensor so to speak.
I'm betting that replacing it will solve all my issues with hard starting, rough idling, etc. once the motor is warmed up.
Thoughts on that?

Coolant temp sensors are cheap and easy to swap out but I suggest getting it scanned to see live data before possibly wasting money and time replacing it. I don't remember if your car would have two sensors or not, some cars have one sensor for the gauge on the dash and another sensor the PCM uses for fueling etc.

It has one. Explains the fans not working. Nothing wrong with them tho. They came on 10 seconds after unplugging the cts. Quit working 30 seconds after plugging it back in.
Engine wasn't up to temp yet and this was just the pcm going into default protection mode but still points to the sensor as the probable cause of them not working.
Of course it could be in the wiring too.
Did throw the 0410 and 0420 codes today too tho.

The fans won't come on until the engine reaches approximately 215° - 220° anyway unless the A/C is on.

Yeah, I believe it's 212 for the primary (driver's side) and 226 for the secondary (passenger side). The secondary also runs when the AC is on. However mine are not being temperature activated at all.