Slow to return to idle

I tried a search but found nothing to help.
I have an '08 4l 6 speed with only about 35000km. My problem is a slow return to idle. By that I mean if I rev it a bit, the revs come down quite quickly to about 13-1500 then it takes a few seconds to drop down to 750ish. This doesn't change much if it is warm or really hot after a long run. The other thing I have noticed is if I am coming up to a red light and either push in the clutch or shift to neutral,the revs don't drop below about 1300 while the truck is rolling. When it stops, then the idle drops.
I have only had the truck for about 4 months so I can not say if this just started or has always done it. I asked the dealership and all they could say was that if the CEL wasn't on then there wasn't a problem. Umm yeah thanks. He wouldn't even tell me if it was normal without writing a work order and reaching into my pocket for $80.
No standard vehicle I have ever had has acted this way so I am hoping someone can tell me if this a common thing and if it is not normal then how to fix it or at least what to check.
Thanks in advance.

 

Yup. My '13 is the same. If I coast down a hill, the rpm is not at idle but instead around 1k. The rpm "hangs" between shifts unless you completely take you foot off of he skinny pedal for a few seconds before pressing in the clutch. There's a few threads on this.

 

It's normal. There is a actuator called and IAC ( idle air control) it's a little valve that opens up when your throttle plate snaps shut so air can bypass your plate. It's to keep you engine from dying. So when your driving the IAC opens in proportion to your throttle plate then when you close the throttle it opens to keep your truck alive and then slowly closes to the desired rpm.

But another type of idle control is instead of using an IAC there is a little motor hooked to the throttle plate and it adjusts the plate at idle to do the same thing.
These systems are almost not noticeable on an automatic but because a manual has so much action with the throttle it will be more noticeable
I'm not entirely sure which system our trucks use. But it is normal. Might be irritating but normal.

 

Also might have to do with speed matching. No one does that anymore eve though it's good to do so

 

That's two things. First, it's the drive-by-wire system - the computer uses a motor on the throttle body to open and close the throttle plate. Toyota eliminated IAC motors at some point (I think concurrent with the '05) and uses the PCM to keep the throttle plate open to establish an idle. If you disconnect your battery for a while, the PCM has to relearn idle position. This can be a problem if your throttle body has debris built up on and around the throttle plate. What the PCM thinks is a "baseline" idle position will be too restricted. Eventually it can relearn around it, or you can clean the throttle body.

The 6 speeds have this throttle "hang" thing (don't know about the 5 speed manual or the automatic slushboxes), and it's an intentional feature. From reading on Toyota's Techinfo site, it's there to ensure enough air enters the cylinders when you clutch-in -- this helps burn fuel in the cylinders and reduces emissions.

Your annoyance is a minor price to pay for saving the planet! or...something.

 

^^ Yup, thats the basic idea, to let enough air in for the fuel already being injected to burn cleanly, thus the slow engine deceleration. Its normal on the V6s at least, and part of the reason so many dislike the 6 spd IMHO, as it makes it harder to shift smoothly especially with higher revs. Takes some getting used to to be able to shift buttery smooth.

 

It sucks but as long as it's normal I won't worry too much. It's a small price to pay for not having to drive a Ford.
Thanks for the quick replies.

 

I dunno. That Raptor is awful sexy. As long as you don't beat on it too hard and pretzel the frame. Lol!

 

So I've found another "have to get used to" with my Tacoma. Piss poor system if that is the case. My truck is always idling above 1k. More like 1.5k. Shifting requires letting off the gas first, then thinking about shifting. Course, I've got bigger issues right now with a collapsed leaf pack on one side. I look more like an old lady going down the road at the moment so it only fits that I should shift as slowly as one too.

 

Does anybody know if this is all true for a 5 speed auto also? If I'm going down the road, let off the gas then shift into neutral the idle won't go below ~1K RPM's until I come to a stop. I've always done this w/my other vehicles (loooooong downhill exit where I get off the highway for work) & they'd drop to neutral/park idle speed (~650-700 RPM's) when shifted into neutral while moving, regardless of speed. My '12, that I've only had for a few days, won't until a few seconds after a complete stop.