Toyota Repair: idling problem, coolant system, vacuum leak

Question
hi i have a 1991 toyota pickup 2.4L EFI and when you press the brakes the engine rpm goes up and down and if you adjust the idle speed it goes up and down  

Answer
Satnam,

Check your coolant leval and make sure there are no air pockets in the coolant system. Next, check to see if your brake booster has a vacuum leak in it. Disconnect the brake booster from the engine and plug the vacuum port to see if the problem goes away. If it does, replace the booster.