1997 XJ Sport, 199,000 miles and running strong. Though the fuel pump (recently replaced but not OEM) works fine it appears the fuel check valve is not working. The fuel pressure at the rail drops fairly quickly after the motor is turned off. There are no fuel rail leaks and the injectors are brand new. I was thinking to install an inline fuel check valve but have a few questions:

1. There are warnings not to install an inline fuel check valve on 1997 and newer XJ's because the high fuel pressure will blow them out. Is this true?

2. If it is okay to install, where is the best place to install?

3. Any recommendations on a brand to buy?

Thanks