Toyota paeso 1991 auto 1500 5E - FHE. Engine cannot idel at 700-900 rev, only rev up and down all the time hot or cold between 1700-2400 air skrew turned all the way in (ie toyota mechanic)still car goes well but uses plenty petrol. Too many vacuum pipes.
Check for vacuum leak, clean out the idle air control valve and EGR/PCV valves-MAF sensors w/electronic cleaner and see what happens-let me know
July, 9, 2012 AT 2:34 PM
If the IAC coolant hoses are both different in temperature, you have a clogged valve or within the hoses and that has to be repaired to resolve. The cold start valve would not be able to close fully at operating temperature.
With throttle fully closed, note if there is a gap with the throttle plate. I have seen throttle plates worn at the sides and you would have to replace the throttle body if that is the case.