my car sometimes stalls out at a stop sign. I got a code 54, which is a fuel pump circuit. I then got a fuel pressure tester, and capped of the vacuum line and the FPR line, and my reading was 45 psi at idle. I turned the car off and let it set for 10 minutes and the pressure dropped down to 30 psi. I put everything back and went for a drive. I got back from the drive and put it into park and it bogged down. I then capped off the vacuum and FPR line and let it idle. It idle, but blew out a bunch of black smoke. Thanks

The fuel pressure you read seems fine.

Did you check the voltage at the pump?

Note:

CODE 54
Trouble Code 54 indicates a low voltage at the fuel pump. If the voltage at terminal "A20" is less than 4 volts for .4 seconds since the last reference pulse was received, the code will be set.
Possible causes include:
1. Faulty fuel pump relay.
2. Faulty connection at ECM.
3. Faulty oil pressure switch.
4. Faulty ECM.