1992 Toyota Idle

I have a 1992 Toyota pickup 4x4 with a 22re 4cylinder engine with a 140,000 miles on it and I am having a idle problem. The idel usually goes high and when I push in the break pedal the idle drops and then goes back up bouncing over and over. I have replace the IAC and the Mass air flow. I took it to Toyota and they replaced the valve Assy Magnet and the diaphragn sub assy and pulled and cleaned the injectors. They then told me they didnt know why it was doing it and said there where no error codes. I wondering if there is something I can do. Any help would be great. Thanks and take care. Also if I let the clutch out a little with by foot on the break the idle goes back to normal. :D