I posted a few weeks ago about an idleing problem with out success.

I have noticed that since the 420 started missing or idleing rough, the fuel tank no longer hisses when I remove the fuel cap. The car runs great from 5 mph to 80 mph, no smoke no leaks.

Any know if the two are related, and what keeps the tank under pressure, what keeps the tank with pressure?

Thanks

__________________
1998 Land Rover Range Rover 66K Miles
1988 300SE Totaled in 1998, hit by drunk driver, but we walked away OK
1989 420SEL 140,000, just warming up. Total by 18 wheel gas truck rear ended, but refused to lose another MB. Had it repaired cost $10,000+ Great Car again SOLD it for a 2003 C320 to save on gas
1991 2500 Suburban 454, 130,000, Best truck in the world. SOLD it out right.
1952 8N Tractor 1,000,000-/+

The tank is not pressurized.
Pressure may build up and should be released when driving through a charcoal evaporation system.

Rob