Miata Mailing List: March 1993, Message #34
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   From: (none)
Subject: Re: RPM drop at stops.
   Date: (none)




I don't have the service manual yet, but my suggestion would be to check the
bypass air valve.  On a multiport fuel injection system there should be a
bypass valve that adjusts the amount of air that gets routed around the
throttle plate.   This valve is controlled by the computer.  Usually, if it's
malfunctoning, the idle will be a little rough too (up/down/up/down etc).  I
had a similiar problem on an Escort GT I use to have.  When the valve sticks or
moves slower than it should, the valve can't get open fast enough and the
engine rpm drops lower than it should, but recovers as the valve opens.

Just a thought.

Dave