Pump turns on and off constantly when in use. It didn't use to so this.

I need the rest of your problem. It was incomplete!

I have worked on compressors from 15 PSI all the way up to 5000 PSI and everyone of the regulators I have seen bleed the pressure of when you dial it down and you can hear it.

True because the constant 12 volt supply is what maintains the settings of radio when it is turned off via the on/off or ignition switch.

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if you have a home entertainment system just turn it on and up kidding the sump pump for our home is always running i have never heard in beep just whines constantly Is the pump still working? I have had pumps go bad before but they never beeped they didn't do anything after burning up the motor i wonder if its a battery maybe 9v

You are correct twice. The antitheft is failing and turning off the fuel injectors. Go to this link for help. This is a classic GM problem and totally 100% related to the antitheft.

http://vatspasslockpasskeysecurityhelp.yolasite.com/

you may not believe me when i say this but your not pulling enough amps from your alternator mine did the same thing its in your belt sytem usually caused by a water pump being out of balance replaced my water pump and runs great! hope this helps P.S. my pump didn't seem to be bad it felt free and didn't feel like it had any wobble but apparently it did

Back pressure is going into the gas pump handle. If you havent already done so, when filling your car play around with putting the gas pump handle tube in at a different angle. My car often gives me the shits doing this too. I find that if I turn the handle so that it is at right angles or even completely upside down with the tube pointing in a different direction within the fuel intake on my car it works fine. Can be frustrating though particularly on high flow pumps.

could be a leaking head gasket but the heater sounds like its air locked have the head gasket checked

The fuel pump is supposed to run constantly when the engine is running. It is pumping fuel to the engine which is in constant need of fuel. It is starting when the ignition is turned on and then shuts down after a few seconds if you do not start the engine. This is exactly what it is supposed to do. You have no problem except for the pump being noisy. On a car that is 22 years old, I would suspect the fuel pump is failing and the noise you hear is it's death nil. Change the fuel filter and if the noise continues be prepared to have the pump replaced. It may fail suddenly or it may become hard to start. If you have never had it replaced just go ahead and do so, to prevent being stranded and a towing fee when it does fail.