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-   -   Jake brake feeling (http://www.tacomaworld.com/forum/4-cylinder/197547-jake-brake-feeling.html)

jpneely 01-09-2012 07:59 PM

Jake brake feeling
 
ok so this has been happening since day 1 and naturally the dealer doesnt have anything to add/help. mainly i was just wondering if anyone else has the same "occurence" as mine.

ok so i have a 2011 4X2 4cyl access cab.

it happens in the morning, it doesnt matter whether its cold or not outside just before the truck warms up. as the truck decellerates and the rpms drop from 1100-800, the truck does a "shudder" deal. the only thing i can compare it to is the feel of the engine braking or if you roll over a small rumble strip on the side of the road.

again its not really bothering anything im just curious if anyone else has experienced this or if im unique

jpneely 01-09-2012 08:33 PM

bumpppppp

tacoman15 01-09-2012 08:35 PM

is it more of a "feel" or a sound? i have had something similar (i think) happen to me too

jpneely 01-09-2012 08:38 PM

its a feeling. but it happens just about every time after its been sitting for over 6-7 hours (night) and before the temp gauge gets above the C (cold)

but also this may just be a 4 cyl thing. ive never driven a 4 cyl before this truck

tacoman15 01-09-2012 08:40 PM

sorry man don't think i can help ya out. good luck

whippersnapper02 01-09-2012 08:42 PM

The computer will not let the trans upshift to the highest gear when it is cold. It does this to heat the engine up faster. So by staying in a lower gear you get more engine braking.

jpneely 01-09-2012 08:54 PM

Quote:

Originally Posted by whippersnapper02 (Post 4330064)
The computer will not let the trans upshift to the highest gear when it is cold. It does this to heat the engine up faster. So by staying in a lower gear you get more engine braking.

that sounds great and all and it makes sense but are you talking about like if you have a stick shift and you downshift to to slow down and the rpms jump UP to slow you down?

the reason i ask is that it feels almost like the opposite. almost as if your trying to start out in 2nd or third. but the (automatic) truck is decelerating...

still not sure if im explaining this in an effective way or not...

AndrewFalk 01-09-2012 09:07 PM

It might just be the way the transmission downshifts at that speed. I drive a 5 speed so I can't say I've experience exactly what you're describing though.

joes06tacoma 01-09-2012 09:20 PM

I had a Dakota that would do that only when cold. It was a sticking Idle Air Control valve. The Tacoma doesn't have that, but I suppose you could have a sticking electronic throttle body.

I have a four cylinder Tacoma at work, but it's a 5 speed.

johnanm 01-09-2012 10:05 PM

It the feeling just for a split second and usually around 15-20 mph? I have felt almost the exact same thing you have, complete with the very muffled rumble strip sound.

jpneely 01-09-2012 10:06 PM

Quote:

Originally Posted by johnanm (Post 4330462)
It the feeling just for a split second and usually around 15-20 mph? I have felt almost the exact same thing you have, complete with the very muffled rumble strip sound.

WOOO im not alone!

johnanm 01-10-2012 01:12 AM

Quote:

Originally Posted by jpneely (Post 4330470)
WOOO im not alone!

I feel the same way brother, it's not going to bother me at all now that I know my truck is normal :)

tacomalex 01-16-2012 07:15 PM

my tacoma, 11' I4 5spd, does get a shudder sometimes when I first start, and sometimes when I stop at a red light or stop sign right after I come to a complete stop..

ffbartlett 01-16-2012 09:48 PM

haha funny that you posted this. mine does the same thing in the morning if i have to stop at the first light. once i get down to about 15 mph it does a quick shudder as I'm slowing and doesn't do it again until the next morning.

jpneely 01-17-2012 09:48 AM

Quote:

Originally Posted by ffbartlett (Post 4372527)
haha funny that you posted this. mine does the same thing in the morning if i have to stop at the first light. once i get down to about 15 mph it does a quick shudder as I'm slowing and doesn't do it again until the next morning.

yup thats it! just once a day. at that first stop sign.

DGXR 01-20-2012 07:15 AM

Quote:

Originally Posted by johnanm (Post 4330462)
It the feeling just for a split second and usually around 15-20 mph? I have felt almost the exact same thing you have, complete with the very muffled rumble strip sound.

Yup me too, once per day, usually just before my first complete stop. It kind of feels like the fuel cutoff engine braking feature, only much stronger and at much lower RPM.

Richardsquid 01-20-2012 02:17 PM

my dealer
 
I have the same thing, my dealer said that since the vehicle is cold, it is still enriching the fuel into the engine. If you were in neutral it would be idling higher than it does once it is warm. As you slow down to stop, the extra fuel keeps trying to keep the idle a little higher so it is sort of like if you had a manual transmission and tried to give it gas in too high a gear, it is basically lugging for a second before the automatic drops out of gear. They said it is more noticeable on newer trucks because the automatic stays engaged longer as you slow down to help emissions. But once it is warmed up there is less fuel so you don't feel it then.

DGXR 01-20-2012 02:54 PM

Quote:

Originally Posted by Richardsquid (Post 4396896)
I have the same thing, my dealer said that since the vehicle is cold, it is still enriching the fuel into the engine. If you were in neutral it would be idling higher than it does once it is warm. As you slow down to stop, the extra fuel keeps trying to keep the idle a little higher so it is sort of like if you had a manual transmission and tried to give it gas in too high a gear, it is basically lugging for a second before the automatic drops out of gear. They said it is more noticeable on newer trucks because the automatic stays engaged longer as you slow down to help emissions. But once it is warmed up there is less fuel so you don't feel it then.

That makes total sense to me... thanks for the education, and to your dealer/tech as well.

jpneely 01-20-2012 07:08 PM

Quote:

Originally Posted by Richardsquid (Post 4396896)
I have the same thing, my dealer said that since the vehicle is cold, it is still enriching the fuel into the engine. If you were in neutral it would be idling higher than it does once it is warm. As you slow down to stop, the extra fuel keeps trying to keep the idle a little higher so it is sort of like if you had a manual transmission and tried to give it gas in too high a gear, it is basically lugging for a second before the automatic drops out of gear. They said it is more noticeable on newer trucks because the automatic stays engaged longer as you slow down to help emissions. But once it is warmed up there is less fuel so you don't feel it then.

that does make total sense! now i have an explanation finally! im glad someones tech is smart in the way of how engines/trucks work...

Canufixit 12-08-2012 05:58 PM

Mine does the same .... mine is a 2012 base, 4L 4X4 Auto ~4K miles. The Solution /reason stated makes sense. one other possible issue that "might" be a cause (although I do not believe it is so in this case) .... a Bad/leaky vacuum booster on the power brake could steal enough vacuum to cause the rough engine vibs .... leaks when cold and you step on the brake ...


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