1999 Volvo N14 random cut off

[SemiSweet]

Check the fuel outlet from the ecm, there is a check valve that clogs easily. There is also a strainer on the fuel pump behind the air compressor that can clog. Make sure fuel pressure is good, new filters etc. Remove and inspect all harness connections on ecm as the wiring on those old n14s can fill with moisture, clean well and put some dielectric grease on the rubber gaskets to help the seal. Check all pass through connectors and wiring to injectors. Also , check the barometric pressure sensor reading on insite, see if it changes at all or is out to lunch as it can cause issues/phantom derates like you mention.