97 Nissan PU lurches when gas is low.

97 PU, 2.4 liter, 4 cyl, 5 speed stick. 62,000 miles. Bought new in 97. When my gas gets down to about 1/8th of a tank, I cannot floor the gas in first gear without the engine lurching like someone was shutting the gas off and on rapidly (like with a light switch). It doesn't happen if I floor it in any other gear with that low gas indication. When it happens, I know I have to fill up to stop it. It has a 15 gallon tank and it usually takes 11-12 gallons to fill it at that point, so there was 3 or 4 gallons left of the old gas in the tank. Perhaps it is that 3 or 4 gallons surging to the rear of the tank and the gas pickup tube is open to the air in the tank, but it is getting some gas to make the engine lurch. I have to remember this when the gas gets too low, so I don't try to jump out into a space in fast moving traffic (i.e. highway merging). If I let off the gas a little from being floored, the lurching stops. It has done this for as long as I can remember. I thought it may be water in the tank, but I have been dumping dry gas and other water dispersing cans of stuff in there, especially when the tank was low, so as to get the most benefit from the dispersant. If the tank is more than 1/8th full, this lurching doesn't happen in first, or any other gear. Any ideas?