off throttle slow down.?

Does Toyota program in something that makes the truck slow down faster when you let off the throttle? it seems as if it almost applies the brakes sometimes.. Even going downhill it slows down really fast it seems. Seems like you let off the throttle, and it coasts for just a second, then something engages and it starts slowing down more. And you can feel it. Is it just in my head?

 

I believe it is the transmission that creates that slight brake feeling when you let off the go pedal.

 

it seems more pronounced than even my manual transmission on my other truck. Just seems more pronounced than anything ive driven before. What is odd is that is seems to lag for a second. About a second and a half after you let off is when you feel it

 

If you're accelerating in a lower gear and let off the throttle it'll feel almost like you're braking (compared to letting off the throttle in a higher gear). That's normal, if that's what you're referring to anyhow.

 

I understand engine brake and what not, vs, rpm, gear shift. I'm referring to just cruising along.. I notice it if I'm going 60, or if I'm going 20.. Its just more pronounced than anything ive driven. This is a automatic by the way. I'm use to driving a standard for the past 10 years.. I know the feeling of letting of the throttle.. Being an auto, this is even more pronounced than my v8 standard, and more than anything ive ever drivin in an automatic. Going down steep hills, it wont speed up or hold speed, it slows down.. But it always has that slight lag for a second before it starts slowing down, which leads me to believe its something programmed in.. Just a weird feeling I'm not use to. But I fully understand engine braking, rpm, and etc etc. I very seldom used my brakes on my old truck.. I just downshift.. cuz 500 hp, and loud exhaust sounds cool on decel haha

 

Pretty sure you're talking about Downhill Assist. Some trucks come with it, IIRC it regulates engine speed and/or brakes to regulate downhill speed

 

Yep they do that. I hardly notice it anymore unless I'm going downhill and it downshifts a gear or two.

 

Yes, if you have an auto truck (with maybe only the tow package?) the tranny shifts down when the truck senses it's just rolling. If you were towing, and it didn't do that, you could still end up gaining unwanted and possibly dangerous Speed. My Tacoma does this.

 

Its a sport model, I believe it has a tow package.. I tried to watch the rpms to see if it was actually downshifting.. but I cant see it actually downshifting.. its as if something else kinda makes it start slowing down faster. But it takes it just a second to decide to do it.. I figured it was normal for sure.. just didn't know why.

 

Nope, DAC keeps the vehicle speed below 15mph.
It's just a normal thing these trucks do. It's good for when you find a cop, don't have to stab the brakes, Just let off the gas... Because face it we all speed.

 

No its not. DAC is on TRD OR AUTO 4x4's 09+ models.... its only activated in 4LO, it keeps the truck at or below 5mph with brake modulation.

What OP is describing is Fuel Cut. To save on gas, when you try to coast, the truck actually shuts ALL fuel delivery off to the motor if certain conditions are met (not going up hill, above ~ 20mph, above a certain rpm etc). This is felt as if the truck doesnt coast but rather brakes for you, yes its engine breaking, as the momentum of the truck is spinning the motor and nothing more. If you have an auto it will go one step further and downshift through the gears (downshifts occur around 1500rpms and are subtle) to keep the rpms above the minimum allowed for fuel cut. Try it out, get on a deserted road, AC OFF (as it will mess with the following) get up to say 50 or 60mph, cruise at that speed for a bit, then roll off the gas, dont touch the brakes and watch n feel rpms as you slow down. You will hit ~20mph and it will ALMOST feel like you just got bumped from behind.... that feeling is the motor actually "turning back on" when fuel delivery is re-applied.


There is also the active transmission downshift(s) on the auto which will occur if the ECU senses you are riding the brakes (not on the gas) but also staying at the same speed / gaining speed, the transmission will actively downshift from 5th to 4th and from 4th to 3rd. These downshifts are very pronounced and in my experience on a hill i have on my commute i can get it to downshift all on its own to 3rd and 2500rpms pretty regularly.

In both cases (fuel cut and active transmission downshift), you can go straight back to 5th gear with fuel being applied by going from D to N back to D (you can do it as quickly as you want). If you have active downshifting occurring, you can step up one gear at a time by going D to 4 back to D.

 

It's normal. I personally love that feature. Even though I still rev the shit out of my engine when going down hills so I don't have to touch the brakes as much.

 

I just downshift to a gear or two and engine brake the whole way

 

whatever it is, it seems more pronounced in this vehicle, being an auto, than in anything else ive ever driven. Some vehicles almost seem to be in neutral when you let off. Down hill they just get faster. this truck does the opposite.. I'm just not use to it, and wondered what really it was

 

My auto did the same thing every once in a while. Sometimes it would jist coast and pick up soeed and other times it would drop a gear and slow down, could never figure out what prompted it

 

It was all explained by "nd4spdbh" above.

Good post by the way.

 

I had similar sensation in my 2007 PreRunner. I previously had a 2006 PreRunner and never noticed it, but within a day or two of getting my 2007 I noticed that it felt like the truck slowed down quicker when I let off the throttle and coasted to a stop, almost like the brakes were being lightly applied. I checked everything I could think of and never found the culprit and I guess I'm used to it now. I also am getting 1 MPG worse gas mileage in my 2007. Both trucks were stock V6 PreRunners, the only difference being that the 2007 is a TRD Sport.