One problem related to rear suspension leaf spring leaf has been reported for the 1998 Toyota Tacoma. The most recently reported issues are listed below.
My 1998 Toyota Tacoma had its left rear leaf spring break just in front of the rear differencial. This cause the leafs to twist inwards and rub against the gas tank exposing the bare metal of the tank. Luckly I took the truck to the mechanic before the rubbing against the tank worked its way through potentially causing an explosion with a spark. At this time I will be replacing the leaf springs (after taking some photos). I have also filed a complaint no 2005-12280233 with Toyota motor corp. Their position is that I will have to bear the cost of the repair as it is out of warranty. I believe this is a potentially unsafe condition and a recall to check leaf springs should be made.