i HAVE A GREMLIN IN MY 1990 964.Car worked fine last year, before removing engine.Only change I have made is the secondary muffler with a bypass pipe.The problem is when the car warms up after five minutes,it wants to stall as soon as the throttle linkage breakes contact with the idle control micro switch. No faults showing,durometric.Any suggestion,s greatly appriciated.Not a lot of porsches in my part of the world.

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This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: The Motronic Engine Management System - 911 (1984-89) -

You have to find out what is happening to the mixture when the idle contact switch opens. Is the car going lean or is it going rich. Do you have a vacuum leak? Try unplugging the O2 sensor and see if the vehicle still stalls off idle. Also you can spray clean your throttle plates and idle air motor.

- Nick