I've had my 1984 Nissan 720 for 7 years now. Early this year the carburetor started leaking around the plunger. I replaced the plunger twice as they were tearing up, then I bought a brand new carburetor. I replaced most of the vacuum lines & it seemed to idle about the right speed when it started warming up. I've also replaced the fuel pump several times, they don't seem to last that long. Most of the time it's OK when driving until I take my foot of the gas, & tho it does not seem to have damaged the plunger in the new carb yet it is leaking around the plunger again to the point it's nearly un-drivable. It has gone dead & refused to crank for quite awhile when just driving down the road a few times. I can't put it in the shop til Monday & not sure I can even drive it that far. Anyone know the cause of this problem & possible solutions???