I know that if the tank gets too low, the car chugs and stuff when youre turning at a higher rate of speed. What would be a safe time to re-fill the tank to avoid all of these problems? At what "gallons left" number?

As a rule, I try to fill my tank when it gets one quarter from empty... I never have any problems that way..

Well you can always look at the guage to see how much gas you have left when it starts running rough like that to find out when you should fill it up. I saw some posts in the DeVille section about this.

I let my car go "E". One time she even showed warning message
like "gas is very low" on the dash. I have no problem though.
She is a Sedan DeVille 95, 4.9L.

My experience (with the 90 deville) would suggest that at the 3 gallons left on the display would be the lowest you should let it go if you plan to turn at high speeds. A few times I have turned at about 35 coming off the highway and the display showed empty or 2 gallons and the car begins to die.

I found tihs post while researching my own issue. My 90 Deville will not go LESS than 3 gallons... I think it actually stops at 3 gallons... whats odd is that the "fuel used" display will continue to change but the "gallons" will not go less than 3 and the range will stop dropping and stay around 60 miles! I'm thinking it stops registering at3 or less gallons

Whenever it get down to 2 gallons, you should fill it to avid that type of problem. Well, atleast I only have that problem when I have 2 gallons left.

I usually re-fill at 4 gallons or my 90 Deville will hestitate when cornering.

My 90 Deville starts chugging at the bottom of 4 gallons during tight right hand turns only, never left turns. But I have continued driving if I know my route is relatively straight - and the gauge will count down to 4-3-2-E. When it hits 2 gallons is when I start getting REALLY nervous. The two times I hit E thankfully I was very close to a gas station! I'm glad to know this is a common problem, I thought it was just another little quirk of my own car (another quirk of many!!)