Engine Racing in Neutral

Can someone point me to an existing thread or forum for the unintended acceleration problem? I have had two incidents where my 4-cyl manual suddenly raced to redline. I bought the truck second-hand last summer. It had only 24,000 miles and I thought I was getting a really good deal. Now I am not so sure. The first time it happened, I pushed in the clutch and coasted while I checked the mat but there was no interference. After pumping the accelerator pedal a couple of times, the pedal released and the RPM's dropped back to idle.

The second instance was just yesterday. I was cruising on the highway when I felt the pedal drop from under my foot while the engine raced to redline. I immediately pushed in the clutch and started pumping the pedal hoping it would release. It ran at redline for about five seconds which made me start to worry about engine damage. I let out the clutch in third gear and the RPM's came down but the truck began to accelerate. When I got back up to 60MPH, I pushed in the clutch and the engine immedately raced back into the red. After a few more seconds of pumping, the pedal released and the engine returned to idle.

The air conditioned was not running (it's winter here.) I was not using cruise control. I could have taken a picture of the mat using my phone if anyone doubts me. There was no interference. This is twice in a six month period. I wonder if the miles were low becaus the previous owner was afraid of his truck. I am taking it to the dealer tomorrow. I would hate to have them simply smile the knowing smile and tell me it is not possible for it to have happened.

 

Welcome to TW

Your rev limiter is doing it's job, so I wouldn't bee too concerned about being at redline for a few seconds.

 

I have no idea. Is there a fuse you can pull for the cruise control to help illiminate that possibility ?

 

I don't think so ...

There's no dedicated 'Cruise' fuse at all. The various components that participate in the cruise control system are powered off a variety of fuses (e.g., ignition, gauge, etc.).

 

I remember reading some where on Toyota's news site something about this. I would take it into Toyota seeing how this seems like a safety issue. When you take it in, stress the word safety with them. I will see if I can come up with the article. Good luck.

 

Another angle ... I'm not sure from the original poster's description whether the engine:

(a) 'slams' to max possible rpm's in one sudden surge
OR
(b) 'ramps up' progressively?

If it 'ramps up' (no matter how fast) rather than 'slams' (all at once) ... It seems to me that a malfunctioning cruise control switch (or two) and / or a wiring fault might fool the ECU into 'thinking' cruise was engaged *AND* the +RES switch was being held down - which would cause progressive acceleration.

 

http://www.newsik.net/cars/toyota/t...probe-on-Toyota-Tacoma-s-sudden-1717831.html#



http://search.yahoo.com/search?ei=U...ykFKO1c3k.rM2JupBLgAAAA@@&fr2=sp-qrw-corr-top

 

For the non-clickers...

 

I've got an '09 2.7 acess cab. I have noticed a hanging throttle on the shift from 4th to 5th. You can shift to nuetral from 4th and the rpm's will stay at the level they were at when you shifted out of 4th, then finally fall to the proper idle speed as the vehicle gradually slows down through 50 MPH while coasting. This is just plain wierd to me

 

Thanks for all the suggestions here. I am taking it into the dealer this morning. I am worried they will not know what to do. One poster suggested that maybe the throttle is sticking when shifting. That's possible. Both times this happened, I was changing gears. However, I had the sensation of the pedal dropping away from my foot. That might have been due to me lifting the foot versus the pedal dropping away. The reason I question this is that both times this happened the pedal was all the way to the floor and I was not "flooring it" when the incident occurred. In the second incident, I tried using the toe of my shoe to lift the pedal up from thre floor but had no success. The one thing I didn't try was turing the engine off and restarting. I keep that in mind for the next time it happens.

 

It is definitely the "slam' variety. It is suddenly running at redline and will not stop.

 

I have not seen any check enging light either before or after.

 

I sawa there had been an investigation. It was closed because they were unable to reproduce the condition and no one could identify a cause for the problem. There have also been many reports of a similar issue from Prius owners which also uses the drive-by-wire design. The fact that they do not know what causes the problem (and therefor default to 'driver error') is not reassuring.

For now, I seemm to have a truck where this problem happend with some regularity. If anyone has any ideas on things to check or test to make while it is happening, I welcome suggestions.