This is a pretty major job. I suggest picking up a Haynes or Chilton manual for your car and following the procedures they recommend.
FriPilot
Yes!
how to remove key cylinder on 98 sunfire
Something...
under the dash
usually on the driver side door
On a 98 Pontiac Sunfire, the red color of wire goes on the terminal marked "B" on the starter. This terminal is located close to the battery of the vehicle.
the 98 sunfire haz a 57.2 litre gas tank
150psi
I have a 98 sunfire with the 2.4L and it is getting about 35m/gal on the hwy.
Have a look at this web site; http://consumerguideauto.howstuffworks.com/1995-to-2005-pontiac-sunfire-6.htm FriPilot
This should help you out; http://consumerguideauto.howstuffworks.com/1995-to-2005-pontiac-sunfire-6.htm FriPilot
if you're going through the trouble of dropping the fuel tank, I'd just put a new one in and be done with it