uncontrolled engine acceleration

"johntyoungjr" wrote in message news: snipped-for-privacy@no-mx.forums.yourdomain.com.au...

Is this happening consistently? Occasionally? Randomly?

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

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" wrote in message news: snipped-for-privacy@no-mx.forums.yourdomain.com.au...

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.

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" wrote in message news: snipped-for-privacy@no-mx.forums.yourdomain.com.au...

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.