In most OBDII cars, there is a "Throttle Position Sensor" (TPS) that is 
among the most replaced items of the environmental sensors. Just Google 
the " ". From one of the pages are the following symptoms:
>
>     * Bucking and jerking of the car
>     * Idle surging
>     * Sudden stalling of the car engine
>     * Hesitation while the driver of the car is trying to accelerate
>     * Sudden surge in car's speed while driving on the highway
>
I think most people would complain of the first 4 reasons and  drive it 
in to a service facility and complain the car is sick or not acting 
right. The last one, most drivers probably would panic, even though, the 
simple act of moving the gear control to either a neutral or a lower 
gear, or pushing the clutch in would solve the immediate situation. 
Turning the key off, sounds good, but most vehicles would result in a 
locked steering wheel. In the case of disconnecting the engine from the 
remainder of the drive line, that same computer is supposed to limit the 
engine speed. On my Cougar, the tach redline is 6500 RPM, but no load, 
the computer limits it to 3500 RPM. The vehicle apparently doesn't have 
the usual 106 mph limiter, since it has been to 110 mph several times, 
no problem.

    * Bucking and jerking of the car
    * Idle surging
    * Sudden stalling of the car engine
    * Hesitation while the driver of the car is trying to accelerate
    * Sudden surge in car's speed while driving on the highway


On another message the brake sensor is questioned. On the Cougar, I was 
hoping to use the reverse switch to indicated when I applied a load the 
the engine, and was surprised to see no action. The car drives totally 
normal with backup lights functioning in a normal manner. I will have to 
add the brake switch data, and see what happens. Sometimes these sensors 
are there for an obscure reason. One of the functions of the brake 
switch is to turn off the cruise control. :)

If the brake sensor should fail, or maybe even the disconnect signal to 
the cruise control, and the vehicle speed sensor reads low, the computer 
would open the throttle to maintain speed (just forget to turn the 
cruise off on slippery pavement and see what happens), and the normal 
push the brakes would not disconnect the cruise. You would have a 
runaway vehicle. At the same time, the intake manifold vacuum would be 
low, and 99% of power brakes (and what doesn't have power brakes today!) 
source of power is the vacuum. The power assist to the brakes would be 
nil, and who do you think that would have enough leg muscle to stop the 
vehicle??  Yes, this is a series of events, probably low probability of 
happening, but... This is why it is important to pay attention to the 
vehicle talking to you, and fix complaints promptly. Besides, it's 
easier to troubleshoot one item at a time.

On 7/15/2010 9:21 AM, Olin Lathrop wrote:
> Vitaliy wrote:
>    
>> "The U.S. Department of Transportation has analyzed dozens of data
>> recorders from Toyota Motor Corp. vehicles involved in accidents
>> blamed on sudden acceleration and found that the throttles were wide
>> open and the brakes weren't engaged at the time of the crash, people
>> familiar with the findings said.
>>      
> But then you have to believe the same computer that might be at fault in the
> first place.  Suppose the problem is that the accellerator pedal (it's a
> long way from the throttle these days) position is misreported, and the rest
> of the vehicle was doing what it was supposed to?
>
>
> ********************************************************************
> Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
> (978) 742-9014.  Gold level PIC consultants since 2000.
>    
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