Probably a thoroughly discussed thing, but I couldn't find anything on it.

2000 5-speed. When releasing the throttle, the revs don't drop right away. Frankly it's quite annoying when trying to shift smoothly. Something wrong with the idle air valve?

 

you might have a dirty throttle body. You're saying they don't drop in between shifts, right?

 

Fidanza Flywheel

 

If nothing has been done to the car in the way of intake/TB work and this has progressively gotten worse, then it could be crud in the TB. Seen more on manual cars unfortunately. This can result in the IACV running out of travel/bottoming out and the Idle Air Control "counts" or "steps" are out of specs. (2-10, requires scantool). In addition to the "hanging throttle", is your idle incorrect/unstable? Any "hunting" or surging in maybe 3rd or 4th gear after quickly closing the throttle? Check the TB for crud around the throttle plate/bore and IACV passage, if so, and there are no other issues, try cleaning the TB (carefully.....don't "flood" the area). After that, accomplish an Idle Air Volume Learn, or make sure you drive the car long and far enough for "relearn" time, before deciding if this was successful or not. Accomplishing the basic TB "adjustments" and getting the correct/stable idle is critical.

 

It doesn't hunt or anything, just 'hangs' between shifts. I just figured the air controller was dirty. It has 115k miles and probably never been cleaned to my knowledge.

 

I'm not sure about the 5th grn, but in the 5.5 it is supposed to do that for a split second or so. Pollution stuff....from what I have heard if the TB reacts instantly unburned fuelvapors exit the exhaust system.

 

Hmm. I'd say it hangs for about 1/2 a second, then drops to a steady idle.

 

I've owned my car since new; it's normal. It's pretty much what brkr said; the ECU keeps the injectors open for a split second supposedly to "help" with emissions.

You just need to adjust your shift timing to keep the surge to a minimum.

 

I kind of feel what you mean on this. I was previously driving my talon (a four banger of course) and it would quickly drop revs when letting off the throttle. The max doesn't drop as quickly though, I feel it has something to do with the added reciprocating mass of the motor and flywheel assy too. It takes some getting used to but the added torque well offsets the rev-happy factor of the 4 cylinder.