Rpm increase when brake and release

I noticed when I’m going downhill, and the truck is picking up speed on its own and rpm’s are already going up, RPMS will spike up, for maybe two seconds, when I break and release. It’s not too much, but still a tad worry some. I have to be going at a decent speed. It’s not every time, but that’s the pattern that I’ve noticed.

 

Downshifts?

 

I’m not sure. Just hope it’s no big deal

 

Mine will spike up due to downshifting if I’m going downhill (seems to be only certain grades) and just blip the brake pedal at around 40mph. I see that as a good thing, using engine braking to help out. Now, instead, if yours was revving while on level ground at a stop with the brakes fully engaged that may be something of concern. My old Accord way back in the day used to do that and it was a Pandora’s Box of problems. Hopefully your case is nothing to worry about.

 

A vacuum leak at the brake booster could cause that.

 

I thought it was the computer doing engine braking.

 

I’m coming from the Tacoma side of things and still learning tundras but these trucks feel very similar. I had the same thing with my 2015 Tacoma. It’s a software thing; when you’re heading downhill and hit the brakes, the trans downshifts so you’re engine braking instead of riding the brakes. Frustrating on long drives but super easy “fix.” I would slap the gear selector from D into 4 and back into D and it would immediately upshift for me. I haven’t played around yet with the tundra to see if the same thing happens but I imagine it would.

TL;DR - next time it happens, go from D to S and back to D.

 

Mine does the same thing. The truck is just downshifting. I wouldn't worry about it

 

Thanks for all of the replies.

 

Normal. Mine does the same thing. It's the computer telling the truck to downshift because you are trying to slow down.