One problem related to rear suspension springs has been reported for the 1999 Toyota 4Runner. The most recently reported issues are listed below.
Upon doing a routine inspection on my truck. The frame on the passangers rear side is corroded to a mechanically unsafe condition. This is where rear anti-say bar attaches and the rear springs. The frame is paper thin in numerous places. Additionally there are more locations on the rear section of the frame on the drivers side that are approaching a simular state. I have washed the truck on a regular basis and used corrosion inhibiting fluid on the frame to prevent this situation from happening. However this frame is undrivable due to safey concerns. I have a 1995 Jeep grand cherokee with 200000 miles and the fame is brand new compared to this.