1999 BMW 528 misfires and code 1397

Ezra, what method was used to extract those codes and did you include all of them?

I used a scanner to retrieve all the codes. They were mostly cylinder misfire. I did found a vaccum hose that was bad and replaced it. After reading several articles here it makes me wonder if it could be fuel related because whenever I sprayed carburator cleaner around the leaking hose it ran great. After I replace the hose It kept running very rough?. Perhaps there is not enough pressure from the fuel pump or pumps?

Where was the leaking hose? What was the size of the hose? You are on the right track mate, your issue is a leak, now we can find the extent of the repair needed.

The leaking hose was a hose from the bottom of the intake manifold to the top of the oil pan fitting next to or attached to the oil dipstick. I've replaced it and it made very little difference. I also hear a pinging noise every 10 seconds when the vehicle was cold?

It is possible the cyclone separator has failed and is causing this issue. BMW engineers like to call this part a pressure regulating valve and the part can be found at Realoem.com and the part# is 11-61-7-501-566. Also consider replacement of the adjacent hoses due to age and possible cracking.

I will look at all the hoses under the intake and the
fuel pressure regulator. Where and how do I test the fuel pressure regulator? does it have a vacuum hose on top like the old vehicles?. Thanks

Ezra, I think there is a misunderstanding and I want to clean it up right now. The site I want you to visit is called Realoem.com. Put in the part number I gave you and look at the part and see where it is. Then we can talk.