I have a 2005 xc70 while climbing a hill the check engine light came on. I pulled codes 301, 304, 300.
I replaced all five coils and all spark plugs still got a code 301. I checked compression in cyl one and three I got 140 psi in cyl one and 160 in cyl three. I swapped injectors one and two with no change. I checked fuel pressure at the fuel rail and got a reading of 45 psi I just changed the filter pressure is still at 45 Psion. the coil is sparking. The plugs, coils, and air and fuel filters have been changed still miss on cyl one and multiple missfires when under a load. I am beginning to think it is a low fuel pressure problem but I get good acceleration under load before the engine starts to miss but it is hard to start. Thanks for any advice.