I am running lean. Engine is pinging under medium load to heavy load (acceleration, climbing a hill. Ambient temperature has been in the 90's but is around 105 this week. The plugs are white-ish on the ground electrode and the insulator and power electrode are CLEAN.... too clean. I checked for massive air leaks but there are none to be found. I have now replaced all of the vacuum lines and the one-way black/white "vacuum" valve is working. If I disconnect the vacuum from the FPR, the idle stays the same. My Nissan and my Fords all have a "tire valve" type of tap to attach a FP gauge. The Volvo appears not to have any place to tap. The connection to the Fuel rail is a hardpipe threaded conection. How are you guys/gals tapping into the fuel line to check pressure. I was thinking of checking the pressure,changing the "under car" fuel filter, Check the in-tank sock... what else and what am I looking for with the fuel pressure. I am guessing it should have a base idle pressure at 40+ psi and then rise (as the FPR loses vacuum signal) to what pressure?