Assuming the '89 tank's the same as the '90, which is plastic, the big screw collar atop the tank, through which the fuel and electric pump lines run, may not be as tight as it should be. Or, if the in-tank pump was ever replaced, the collar with its big o-ring may not have been threaded right. It's easy to screw up. My '90 wagon had slight leakage and/or gas odor, though only when filling up. When I had to replace the in-tank pump, I reassembled everything correctly and no more gas leak.