MATE ! I've been having the EXACT same problems / Symtoms - power loss , code 77 fuel injection timing etc , was told injector pump but like you didn't want to spend that kind of money & still not fix the problem , after much trial & error - inspecting tank - clean , pressuring fuel lines - no leaks , I then discovered primer pump on top of filter housing was hard after 1 pump whereas a few mates with same engine said they'd have to pump there's a dozen times - anyway I bypassed the standard filter / housing with a Ryco inline filter & fixed it straight away !!!! What a fukn relief I telya . Ran it for a month with NO dramas - put it back to standard & 2 days later the problems started again . Wanted to pull housing apart to see what's happening in the there but it's pressed together so I wrapped a white rag around the outlet to catch anything & blew into the inlet with the compressor , found nothing but it's been hooked up back through standard filter now for months & NO dramas . Hope this helps . & yes I put about 6 or 8 filters on it - both free market & genuine Nissan .