Im lost, 88 IROC 5.0TPI and it just started acting up. Here we go, Today it started running rough at idle and then cleared up, no prob. Now it smells like gas, the vent hose up to charcoal canister has gas in it but not leaking out the bottom, its also hissing(gurgling) and it sounds like the fuel pump is running even with engine off and the harness disconnected. WTF? Loosen the gas cap and it has built up loads of pressure even though the car has shut off, put cap back on and does it again. No black smoke from exhaust, not running rich/lean, fuel pressure OK. It stumbles at take off sometimes, please help, TIA. TIMMY!!!

 

Something wrong with the tank vent system. The canister should only contain gas fumes, not liquid fuel. Seems that the venting cycle is not taking place, purge valve may be stuck, or the valve is not being activated.