With compressor engaged, 35 to 45 lbs.
That would be a OBD II system. You need a code scanner to read the codes.
Fuel pressure should read no less then 9 LBS. and no more then 13 LBS. And yes it should hold the pressure with key on, engine off.
It should list the cold tire pressure for all tires.
46-51
blood pressure can be too low and too high, if it is over 140/90 you should think about seeing a doctor.
There's a sticker on the driver's door frame that tells you. If you can't, read the tire sidewalls.
13.9 to 14.3 VOLTS with engine running.
Read the tyre wall, it should have the pressure envelope there. Any pressure within that range should be okay. If you want less rolling resistance inflate the tyre to the higher end of the range.
You may have fuel pressure but not enough. Have the fuel pressure tested with a gauge, it should read between 60 to 66 psi for the injectors to work. Also check the fuses to be sure none are blown.
800 RPM should yield about 25-40 lbs. of oil pressure on a stock motor.
a strong engine should read between 150 and 180 pounds of pressure in each cylinder.
blood presure read 158/102