what maintenance does the vehicle need at 87,000 miles?
Do you have a service manuel or a list of maintenance items for the 1998 4Runner?
You are darn close to 90k miles, which means I would consider doing the services recommended at 90K: coolant flush, transmission flush, oil change, new spark plugs and wires, and a new air filter. If you want to avoid doing this right now, you would be fine with an oil change. At 100k miles you should look into having your timing belt replaced if it has not been done yet. Also, consider having your tires rotated if you have not done so in the last 6,000 miles. Most places will also add a brake inspection and suspension inspection at 87-90k miles, which basically means they'll pull your wheels and check brake pads/shoes as well as suspension components like shocks, struts, sway bar bushings, etc.