Uncontrollable Acceleration

Hello - I have a scary experience the other day with my 1996 Toyota Avalon, which has 175,000 miles on it. I was sitting at a traffic light and the ROM started going up. I had to press the brake hard, or put in in N to keep it stopped. In traffic, I couldn’t touch the accelerator pedal and had to control the speed by shifting back and forth between N and D. The resting RPM without touching the accelerator pedal was about 4000. On the open road, the car would do 50 mph without touching the pedal. If the accelerator pedal was touched, the engine would race to 6000 rpm and then slowly subside to 4000. After a few miles, the problem corrected itself and the Toyota garage couldn’t find anything wrong with it when I got the car there 30 minutes later. Kind of scary. Any ideas?

I suspect the idle air control valve, OR, the engine computer (PCM) controlling it. The valve may have become stuck. There are cleaners for this. Is the check engine light (engine symbol) on? If it is, go to a large auto parts store for a free scan for the trouble code.

Thanks for the suggestion. No, the check-engine light did not come on.

My mother has the same 1996 avalon, only 75,000 miles on it & in very good condition except for the following incident. She had a similar & very scary problem last month. She was driving on a local road coming home, when the car started to accelerate. The brake was of no use when she depressed it all the way. Thank god, luckily she was able to turn into the long uphill driveway of her apartment complex and steer towards an empty area in the parking lot. She put the car in neutral and continued to try to brake, but it continued to cruise along with a mind of its own. Finally she was able to “stop” by aiming for the curb at an empty series of parking spaces, and her car went up onto the curb and hit a lamppost and tree, and finally stopped.

Afterwards, the police turned the car on & it immediately revved to over 5000 RPM w/o any touch to the gas pedal. The roadside rescue mechanic tried it out as well, and found the accelerator pedal stuck down. They freed the pedal, gave it some gas, and it stuck again. The brake also stuck on the floor when they pressed it.

My mother had the car body repaired, but the mechanics could find nothing wrong w/ the pedal and said it wasn’t the usual greasy pedal thing that’s been subject to recall, nor floor mats. She took it to a Toyota dealer, they poked around a long time and finally said it was a problem w/ the cruise control. Now, I know nothing about cars, but I see from their huge $2,700 bill that they replaced the accelerator link assembly, accelerator link / cruise actuator, accelerator cable assembly, speed actuator assembly, and some less expensive parts. I think it’s unconscionable, but not surprising, that Toyota would not pay for these repairs. They should be grateful that no one was hurt in this case.

My question is, were these repairs valid? Why and how on earth could cruise control hijack the control of the accelerator, disabling the brake? She did not have cruise control turned on, and in fact never uses it. Normally applying the brake would cancel cruise control. Has she been completely ripped off by the Toyota dealer who was just trying to make a buck and get her off their back?