High idle at stop

[Jack Russo]

I have an 1987 GN, 54k miles. Totally stock.
Recently after driving a bit and coming to a stop (stop sign) i would feel the engine rev high then drop down.
So i put it in neutral, and the RPMS go up to about 1800 then drop down to normal 750-800 range.
This happens everytime i stop driving and stop the car. I actually put the car in neutral to lesson the burden on my foot.
Vacuum leak would you think?
other than this the car idles normal at all other times.
Thanks fellas (and ladies)!

 

[Lil Truck]

Possible sticky PCV valve, also listen for a vacuum leak.

 

[aminga]

Scanmaster data?

 

[earlbrown]

If it's truely 'totally stock' it needs to be parked until EVERY weak link and need for PM gets taken care of.

There's no reason to tune around weak fuel pumps, 1/4century old injectors, poor chip programming, flaky MAFs, etc...

 

[riviera]

My car do the same thing but only when I first start the car it will have a fast idel. Do anyone have and idea what that my be

 

[earlbrown]

That's normal. They idle fast until a certain temp is reached. Same as a fast idle cam on a carb.

 

[LEW_86]

Do you have any way to check and see if the ECM is recognizing that the car is in park or neutral? Maybe the p/n switch needs adjusting.