How long can a Z car sit? I have 2 that I'm neglecting a little bit while I'm working on my newest one. I charge their batteries once a month and crank them every weekend I just don't drive them. I'm worried about the fuel sitting still in the tank. I can't decide whether to fill the tank or leave it lower because I won't be driving them. I know this isn't the worst problem to have but still a worry to me.

Thanks for any recomendations.

Keep fuel tank close to full to avoid the effects of condensation.

Add some Stabil to counteract the ethanol degradation if they are sitting for months or a long time.