Get some carb cleaner or starting fluid. Spray it around the area of the intake plenumn. If you have a change in idle speed wen you spray, you have a vacuum leak somewhere. If so, use spray to isolate exact area if you can.

Pay close attention to the area between upper and lower intake. Also, ensure you have no cracked or loose hoses to your intake. Check the hose on the bottom of the plastic intake tube after the air filter and before the throttle body. Check fit of hose that goes to power brake booster. Report back what you find.

99 Gen 2.5, fixing blown head gasket
89 SWB- 33's, ARB Front locker, SR rear locker/axle, SR F brakes, winch, WST Offroad Armor all Around, 2.85 Aussie T-case Gears (SOLD)
Sold: (2) 95 SR's, 86 SWB, 90LWB, 91 LWB
-Can Change a timing belt in my sleep..