The diagnostics go away when the battery is disconnected, so if you get any it will be from the time you put a good battery in the car.

Four months will not create bad gasoline, a little water in the bottom of the tank if the tank was 1/2 full or less. When you checked the fuel pressure, did you notice any water?

When trying to start this car and you suspect the lifters being flattened, just floor the gas pedal and keep cranking for at least two solid minutes. The engine will sound like it is easy to turn over and turn rapidly. When it starts to labor or turn harder, the oil pressure should be building and it will slowly come to life.

Klaus
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Just driving a 1998 V70R :)