Jim Grant's Tech Tips
Mazda 929, High Idle
a ‘92 Mazda 929 and it’s idling way over 2000 RPM. I also
have a check engine light, on what can I do about this problem?
suggestion? Start first with the check engine light. My reasoning? When
the check engine light is on in a Mazda of your vintage there has to be
a system problem. The early On Board Diagnostic (OBD I) systems were really
on the loose side of acceptable tolerances, simply meaning that something
has to be really broken before the check engine light is turned on. The
same computer that turns the check engine light on performs the idle control
on your Mazda as well. So, if the computer is upset about something and
the idle speed is out of control it is likely the diagnostic trouble code
from the computer will provide a solution to the high idle. Have a technician
ask the computer what it is complaining about and you just may have the
answer to the other problem.