Odd throttle issue

[mr_miles]

I've been chasing an odd issue with my car for quite some time now. Periodically while driving regular freeway / highway speeds of around 60 to 65 mph, my car will hold 3k rpm on it's own. I imagine I could do it at any speed so long as I hold that rpm range. I can let off the gas and the car will actually maintain speed like cruise control is on. It is not. Using cruise control negates this issue. Putting it in neutral, the car will rev itself to about 4k, hold, and drop down to idle. I do not know what circumstances cause it to do so, either. sometimes it does, sometimes it does not.

I have no idea what to look for on this. resetting the ECU does not fix this issue. It does not throw codes or have any stored either. it's almost like.....it's normal for it haha. I also have no idea when it started.

my mods are as follows:
Afe intake
Lightweight pulleys
Megan header
Megan axle back
Nothing else engine side anymore that could cause it.


I am confuse.

[CTScott]

Does tapping the accellerator when it is happening have any effect?

[mr_miles]

Yes, that ends the cycle and it goes back to normal until it decides to do it again.

[IllusionX]

have you cleaned your throttle body ? I am thinking either that, or your pedal is doing free game.

[CTScott]

Originally Posted by mr_miles

Yes, that ends the cycle and it goes back to normal until it decides to do it again.

Agreed on the throttle body cleaning mentioned above. Do you by any chance have an OBD device that you could use to monitor the TPS and some other parameters that might shed some light?

[kou]

I had dealt with this issue for a few years and never figured it out. It actually got scary sometimes when your expecting some engine braking and you get some acceleration. once I changed to a 1zz TB issue went away.

[mr_miles]

the throttle body is spotless - It's spent a fair chunk of it's life on a shelf as I had a 1zz throttle body and the M/I intake manifold. I had this issue with that setup, too...I had actually accepted the fact that it may have been from those two combined with everything else that's modded, and didn't bother.

I have a bluetooth obdII reader I can use, but I have to find a new app as Torque wont work properly on my galaxy s5 (no menu button on the phone lol)

[Exiwolfman]

I wonder if u may need an update for the ecu ...its quite common procedure

sent from Mars using Moto g !

[CTScott]

Originally Posted by Exiwolfman

I wonder if u may need an update for the ecu ...its quite common procedure

sent from Mars using Moto g !

There are no updates for the 2008. There is one for the 2007, but it is related to an over sensitivity for the crank position sensor.

If the problem occurred with both throttle bodies, I would suspect that the issue is with either the accelerator pedal or with the ECM itself.

If you want to try swapping the pedal, I have a spare. I would be willing to ship it to you for just the cost of shipping, so you can test if it resolves the issue. If it solves it we'll figure out a price. If it doesn't, then shoot it back to me. I could do the same with an ECM if I have the matching one to yours. Grab the part number off yours.

[mr_miles]

You have an ecm for a 3rd gen already? :o

This has made me realise I have not updated any of my info stating i drive a 2013, nor did I say so in this thread haha. I imagine pedals are the same, though. Might start there after I see if I can gather any more info from the obdii reader.

[IllusionX]

You should read again. lol i see nowhere mentioning 2013 anywhere in this thread.

[CTScott]

Originally Posted by mr_miles

You have an ecm for a 3rd gen already? :o

This has made me realise I have not updated any of my info stating i drive a 2013, nor did I say so in this thread haha. I imagine pedals are the same, though. Might start there after I see if I can gather any more info from the obdii reader.

For the 3rd gen both the ECM and accelerator pedal are different.

[mr_miles]

Go figure. Lol. I was unable to get the car to do it on my way home from work this morning, we'll see if it will do it here in a little when I go to work.

[suzukirascals]

hi. my 07 D4D is complete opposit. While driving whithin a line of traffic at lower speeds & with my foot just resting on pedal at a constant speed it completely reduces itself to idle. If i quickly pump the throttle pedal it comes back to life. The engine never cuts out. I replaced the fuel filter but it now seems worse. However my wife hasn't had any problems since i replaced the filter but she only uses car for short journeys to & from work. Perhaps it only happen's on longer journeys?

[bronsin]

I bet (ha ha) if you remove the mods you made the problem goes away.

[mr_miles]

I tried putting the factory air box back on and it still happens. I gave up. Eventually I'll go to Toyota and make a fuss until they figure it out lol.

[mr_miles]

I went to Toyota, and the guy I spoke with was almost reluctant to help me mostly because I think he had no reasonable idea on how to help me, he seemed afraid to help because it's a potential hazard I guess. He asked a tech and the tech said the best they could do would be to go for a test drive and go from there (no shit, right?) and it would cost me at least the regular maintenance fee. I don't have any warranty time left, but he suspects a manufacture warranty would hopefully be in effect. Bleh.


I did notice that while this event is happening, if I put it in neutral and maintain my speed (downhill, etc), it revs up to 4k. If I slow down with the brake pedal, it almost immediately drops to regular idle.

If I use the E-brake to slow down, once I hit between 50 - 60, it force drops to regular idle. It does this if I slowly stop, or stop faster.

I can also force the event by accelerating above 70mph. 60-70 seems to be hit or miss for the event.

I have an idea though! The rear hubs each have a speed sensor, correct? is it possible one could be failing in such a way that is fooling the ECU to think the car needs to be revved? or is there a speed sensor / shift sensor in the transmission that may be causing an issue? I've always noticed upon shifting during normal driving conditions, the car does seem to very LIGHTLY blip the throttle when I shift. Even with my foot off the gas.

[CTScott]

Originally Posted by mr_miles

I went to Toyota, and the guy I spoke with was almost reluctant to help me mostly because I think he had no reasonable idea on how to help me, he seemed afraid to help because it's a potential hazard I guess. He asked a tech and the tech said the best they could do would be to go for a test drive and go from there (no shit, right?) and it would cost me at least the regular maintenance fee. I don't have any warranty time left, but he suspects a manufacture warranty would hopefully be in effect. Bleh.


I did notice that while this event is happening, if I put it in neutral and maintain my speed (downhill, etc), it revs up to 4k. If I slow down with the brake pedal, it almost immediately drops to regular idle.

If I use the E-brake to slow down, once I hit between 50 - 60, it force drops to regular idle. It does this if I slowly stop, or stop faster.

I can also force the event by accelerating above 70mph. 60-70 seems to be hit or miss for the event.

I have an idea though! The rear hubs each have a speed sensor, correct? is it possible one could be failing in such a way that is fooling the ECU to think the car needs to be revved? or is there a speed sensor / shift sensor in the transmission that may be causing an issue? I've always noticed upon shifting during normal driving conditions, the car does seem to very LIGHTLY blip the throttle when I shift. Even with my foot off the gas.

The hub speed sensors are only used for braking.