randomly - idle drops to 4-500 after putting in park (atx) doesn't stall - ideas?

[winston3x]

Hi,
as the title says, sometimes after putting the car in park, the idle will drop and almost stall out but doesn't. Happens only intermittently. The car will be having major service soon (timing etc..)
just want to know if I should tell them to check something else. Thinking about replacing pcv while they are in there. any thoughts, advice?

 

[MaxPower]

The intake (accordion) tube from the air intake box to the throttle body might have a small crack in it. This is one of the most common causes of a rough idle on a Protege.

 

[winston3x]

accordion tube was replaced a few months ago, although maybe one of the fastners is loose.

Also, when the this happens the headlights and instrument cluster will dim until the idle gets back to 700.

 

[99prolx]

The only reason the headlights dim is because the alternator isn't charging hardly anything at that low of an rpm. Like max power said there might be an air leak not being metered by the maf sensor. Check the intake connections including vacuum lines connected to the manifold. Maybe one is cracked