Loses fuel pressure when parked

hello bimmerfest i am new to the board but have used many tips from the board. I would appreciate any suggestions. I have a 97 e38 with m62 motor I recently changed fuel filter and two weeks later my car would lose fuel pressure after sitting for 5 minutes or so. I went under the car and noticed while the car was running the fuel line had plenty of pressure soon as i turn the motor off withing 5 minutes it would lose pressure. Trying to fix this i have changed the fuel pressure check valve in the tank, the regulator and fuel pump. After car cranks for a while it starts and runs perfect! I have noticed no gas smell coming from from the lines or around the car. Please help. Car has 250,000 and runs great!
i have also changed osv, cooling pipes, intake man gaskets, and crank position sensor.

Try clamping the rubber parts of the fuel supply pipe and fule return pipe, one at a time. That will tell you which way the pressure is being lost. If neither make any difference (ie you still get a loss) it points to leaking injectors or an external (pipe) leak. Not much fuel needs to leak to reduce the pressure. Also join in a gauge if possible to watch the pressure go down.

After checking the above mentioned I would check if the fuel injectors are leaking. Order some new o-rings, remove them and check you tube for tutorials how to check them and clean them also. There are a lot of videos. If you want to find which one is leaking you could check the spark plugs for deposits.

If you suspect leaking injectors get them rig cleaned and tested. Bit $ but the results are

Thanks guys for your reply. I am going to clamp and check fuel lines. If injectors were leaking would I smell fuel? I have recently changed injectors but had this problem before hand.