Driving on interstate at 65 mph, the ABS warning light came on, and the speedometer started jumping erratically from actual speed to lower speeds 45, 25 + others as low as 8 (eight) mph. This caused the transmission to downshift unpredictably, over-revving the engine speed. It happened repeatedly so I documented the odometer erratic movement on my cell phone as a video, showing road movement + all gauges + audio events like engine over-revving at same time. The video is of high quality and the events taking place are documented with the video. Rural area with few cars on road at the time. If it took place in a city interstate environment (especially in the winter months) it might have caused a multiple car collision with sudden unexpected downshifting that was out of my control. Engine RPM also hunts erratically and out of my control. Predictable in what it does, it begins approximately within a range of 4-8 miles after leaving home daily. When engine turned off and parked at a local store as an example, it will clear it's problem as if a cpu is "re-booted", and repeat the cycle of erratic behavior from that new starting point. When I bought + installed actron brand obd-II code reader which features ability to reveal ABS brake codes, it never shows any other stored codes except a single PO446 which is an emissions related code. This van was originally sent new by the selling nh Chevrolet dealer to the Pennsylvania based quigley conversion facility, so in February 2004 was modified from rwd to a 4WD by exchanging stock model 2500 front end for a 4 wd pickup truck new factory front end with 4wdl, neutral, 2wdh 4wdh floor control lever. The driver's door jam has an 8600 lb gvw certification which is appropriately quigley's. my very low odometer at 16,614 miles is accurate, as I also have other vehicles to use, and work at home.

- Plainfield, NH, USA

Contact owns 2003 Chevrolet Express G3500 passenger van. The van will accelerate on its own sporadically. This started around 7-20-05. It does it while stopping at stop light and it will also do it while driving on the highway. The idle speed control motor, throttle position sensor, cooling sensor, ECM, and the prom have all been changed within 5-6 weeks. He says it did it at any speed sporadically. He made an appointment to bring the car in again for a possible repair. The check engine light will usually come on after an incident.

- Locust Valley, NY, USA