N13 high fuel pressure ongoing issues

I have a 2014 prostar with n13 I need help with. Nobody, including international, can find this problem. I get spn 3055 fm0 and fm17. I also get spn 157 fm0 and 14. I also get a funny noise like a restriction or air bubbles (like sucking on a straw too hard). I have already replaced the fuel rail pressure relief valve, checked grounds, replaced fuel filters and checked lines. Fuel system cleaner seemed to be making improvements but today I noticed that the fuel pump is leaking diesel like crazy. I already ordered a new pump but I would like some insight on this issue as to whether or not a leaky pump could cause high pressure (air bubbles) or if there is another problem that like to hide on these before i blow up a new pump. Any advice (other than "buy another truck") would be greatly appreciated.

 

Thanks heavy d. The return pressure has been checked, at one point it was diagnosed at the dealership which is when I had the relief valve put in. I'm just hoping that the leaking pump was sucking air, it is definitely acting up way worse with the same codes since it starting leaking lots of fuel. Once the new pump is in I'll see if I can get codes to pop and update. This has been a great truck but the pump causing too much pressure is just bazaar and has been fairly costly to find. As an old auto and motorcycle tech I was looking everywhere else. Oops.

 

That sounds about right for how it's acting

 

I don't ever put anything but good diesel in my tanks, the tanks are clean and the fuel filters have been changed a couple times. The lines and return pressure have both been checked on more than one occasion, however, they did have a brittle line break removing the pump. That could've been another issue I suppose but it does appear the pump was the entire issue. Probably sucking air before it started noticably leaking. Either way, it's running smooth and quiet, even better than ever at idle and all throughout the band. I need to find a trailer still, but I could get it to pop codes by putting the spurs to it and getting the rpm's up and it's running flawless with no codes coming up. Thank you guys for the responses. I have peace of mind this thing is finally fixed. Next time this sort of thing happens I'll be looking at that pump sooner than later. It's expensive but so is screwing around with it for months!