uncontrolled engine acceleration

[johntyoungjr]

My 1996 Avalon just started accelerating uncontrolled...i.e. without using the gas pedal and the cruise control is not on. Any suggestions on wht is causing this?

"johntyoungjr" <johntyoungjr.2jatkb@no-mx.forums.yourdomain.com.au> wrote in
message news:johntyoungjr.2jatkb@no-mx.forums.yourdomain.com.au...[color=blue]
>
> My 1996 Avalon just started accelerating uncontrolled...i.e. without
> using the gas pedal and the cruise control is not on. Any suggestions
> on wht is causing this?
>
>
> --
> johntyoungjr[/color]

Is this happening consistently? Occasionally? Randomly?

How much is it accelerating? 100 RPM? 1000 RPM?
--

Ray O
(correct punctuation to reply)

[johntyoungjr]

The problem just started today. I had to apply the breaks every 10-20 seconds to keep the speed below 35 mph (city streets). The engine started racing when I stopped but I did not notice the RPM.

"johntyoungjr" <johntyoungjr.2jaz4a@no-mx.forums.yourdomain.com.au> wrote in
message news:johntyoungjr.2jaz4a@no-mx.forums.yourdomain.com.au...[color=blue]
>
> The problem just started today. I had to apply the breaks every 10-20
> seconds to keep the speed below 35 mph (city streets). The engine
> started racing when I stopped but I did not notice the RPM.
>
>
> --
> johntyoungjr[/color]

Without seeing what is actually going on, the problem sounds more like a
high idle speed than uncontrolled engine acceleration.

Make sure that the throttle cable linkage is not binding and that the bell
crank on the throttle body is returning to the full closed position.

Check the idle air control valve on the throttle body to make sure it is not
sticking.
--

Ray O
(correct punctuation to reply)

On Sat, 23 Dec 2006 21:27:03 -0500, johntyoungjr
<johntyoungjr.2jatkb@no-mx.forums.yourdomain.com.au> wrote:
[color=blue]
>
>My 1996 Avalon just started accelerating uncontrolled...i.e. without
>using the gas pedal and the cruise control is not on. Any suggestions
>on wht is causing this?[/color]
Binding throttle cable? Dirty throttle body? Vacuum leak? Leak in air
intake ducting?
What have you observed in the visual inspection that you surely made
by now?

Something in the control loop is telling the process controller it needs to
add fuel. Have a competent technician determine the fault, before you take
it on the road, WBMA.


mike


"johntyoungjr" <johntyoungjr.2jatkb@no-mx.forums.yourdomain.com.au> wrote in
message news:johntyoungjr.2jatkb@no-mx.forums.yourdomain.com.au...[color=blue]
>
> My 1996 Avalon just started accelerating uncontrolled...i.e. without
> using the gas pedal and the cruise control is not on. Any suggestions
> on wht is causing this?
>
>
> --
> johntyoungjr[/color]

I've seen two cases of "unrequested acceleration", and both cases were
caused by rodent nests in the airbox. The little nuts and twgs these guys
were stowing in their new home were intermitently getting sucked down the
intake boot and lodging themselves in the IAC motor, preventing it from
closing completely. They would stay in there for a minute or so and
prevent the engine from idling under 2000, then dislodge themselves and
everything would return to normal until the next time.
Just something to think about.