ISX in a Volvo low fuel pressure

[Ronnie4447]

Low fuel Pressure
Sent this to Rawze in a PM and he made a few suggestions (Thanks a Million Rawze) He suggested that I ask here also. I hate to be a bother and ain't no green horn but this is driving me crazy. Please explain how to test your suggestion I'm stupid when it comes to this electrical junk. I did find a loose wire on the fuel shut off solenoid and could make it do it or stop by moving wire, cleaned everything and tighten and still does it but only getting low pressure fault now not low pressure electrical fault also.

I got a problem with it running rough. no smoke and only notice when idling low or high idle. It doesn't do it all the time and is unpredictable. I thought it was fuel filters, not so. It is a 04 ISX 400ST in a Volvo. the dash diagnostics shows low fuel pressure. and low fuel pressure electrical fault. The engine has 270k since rebuild and I put a new primer pump on it when I built it (long Story why) any suggestions where to look? I don't have diagnostics program just a poor old O/O that is tired of getting jacked by these parts puller shops. Any help is greatly appreciated, if I can't figure it out I'll just run it till it blows or quits then I will know what too fix. If you need to call me my number is xxx-xxx-xxxx (pm me for it) thanks again Ronnie Burt