Engine reving stays when let off gas

Driving down road, highway speeds, when i let off the gas pedal the engine stays revved for 5 to 10 seconds before it drops.

Any idea, any tsbs? in shop now, they dont have a clue

 

Is it manual?
If it’s manual then it’s throttle hang, normal on some modern engines with manual trans (including Tacoma) and highly annoying.

 

5 - 10 seconds sounds way excessive for normal rev hang though...are you sure it's really that long?

 

What do you mean? Video?

If you’re in gear.. its going to stay “revved” up.

 

Sounds like an auto trans...

DO you mean - After accelerating and the truck downshifts, I let up on the gas and the revs stay high for a few seconds?

 

i have noticed this too. just drive normally at say 40mph and then almost floor the petal and then completely take your foot off. the revs hang for at least 5 seconds or so

 

That’s not a problem. It’s staying in a lower gear in anticipation that you’ll need it.

 

mine does this too even after the tsb. hangs in 4th-5th for a while even after letting off at 65+

 

Auto transmission. Driving down the highway are you in the Side Road and if I'm accelerating say around 3000 to 3500 RPM and I take my foot off the gas pedal the engine continues to rev at 3500 RPM like it's still getting gas. I do the same thing but around 2000 RPM or with any other vehicle for that matter and I take my foot off the gas pedal the RPMs will drop at the same time because no longer being fed gas.
Not new to driving not new to newer vehicles this is not normal

Took the truck in of course dealership says that they couldn't reproduce come to find out after I was driving away there road test was about a mile if that by looking at my odometer

 

My 2nd gen used to do this pretty badly when I first bought it in 2011 (not lying, I have posts on TW from 7 years ago to prove it!). Push in the clutch pedal and engine speed would hold, or rise, for 5-10 seconds. Shifting from 4th to 5th was like dumping the clutch every time. Dealership was the same way, couldn't reproduce.

Anyway, it gradually went away over time. I don't know if I learned to work around it or if the ECM learned my shifting habits. I think a cmbination since it does it when I disconnect the battery but only lasts for the day or so after reconnecting.

All in all, it seems like something built into the ECM by Toyota. I would try disconnecting the battery overnight and seeing if that helps any. Possibly reteach the ECM to drop RPMs by touching brake pedal after letting off throttle. Seems archaic, but might be worth a try.

 

I don’t have rev hang, 4cyl manual. If that helps.

 

I have 6 cyl manual, rev hang is absolutely brutal on my truck. So annoying.

 

Carbon Build Up, you been babying it too much. It wants to get up and go.

Fix it by "Stand In It" till it tops out at 120.

 

Rpms are controlled by what gear you are in...not the amount of pedal pressure. So if the transmission holds a lower gear for a short time after you have been aggressive with the throttle, revs are going to stay high as well. Older vehicles didn't lock the torque converter as much as newer vehicles, so the rpms would drop off more immediately with reduced throttle. Now the transmission stays locked to the engine....holding rpms high until an upshift occurs.

 

My truck has no torque converter. The rev hang is because the ECU is injecting fuel after I have stopped commanding it. I think it might be anti-stall compensation. Part of it is the inertia in the rotating masses in the engine.

If I put the truck in neutral and blip the throttle, it takes a loooong time for the revs to come back to 600-800 idle rpm.