Hi,

I have a '90 Nissan Bluebird and have had trouble with the 'idle air
control valve', according to my Nissan mechanic, where the car had a
high idle and was prone to jerking. This valve was replaced with a
second-hand one and both problems were fixed, until a couple of weeks
later when the jerking reappeared. I decided to look at the other two
controllers/sensors that are located around the same region on the
throttle body, where air comes in for idle. I cleaned one out, it was
filthy, and it consisted of a little plunger, is this the choke??? The
other controller or sensor consists of a smaller plunger which is
spring loaded and sits close to the screw which can be adjusted to
alter the base idle speed, does anyone know what this???

After having cleaned up the mechanism which I think is the choke, the
car now does not come down from high idle when the engine warms
up...have I cleaned away more than I should have? It looks like the
mechanism works using an electromagnet to push the plunger in/out of
that part of the throttle body to reduce/increase air into the system.

Any help would be greatly appreciated,
Daniel