New to site and having trouble with VQ 4lt,started to stall intermittently and eventually wouldn't start at all. Diagnostics wouldn't log unless it occurred when connected. Eventually mechanic got a read for cam speed sensor error which now replaced but can't get compression to cylinders(variable cam oil pressure?) and leaving plugs wet. Anyone had similar issue?150000 on clock and hasn't missed a beat until now. Any advice would be appreciated cos it's getting pricey and No-one seems to have a clue including Nissan