I think you have an accumulation of water in the gas tank, due to condensation.

Start throwing in some gasolene additive products that advertise removing water from the fuel. They typically have some alcohol content, and water is able to mix with the alcohol and run through the system.

The symptom that leads me to this esteemed Internet diagnosis, from hundreds of miles away is your comment about coughing and sputtering when rounding a corner. During that condition water is able to slosh up to the tank drain.

Besides running properly, keeping the water removed from your tank keeps it from rusting, and scaling-off rust is a bad thing to have in your fuel system.

Hope this is it - relatively simple.......

Ken300D