Hello!
On a 2003 Chevy Venture with V6 SFI engine and 4T65-E transmission I have a problem - when forcing the gas pedal, the speedometer drops and shows wrong speed and the transmission tries to shift to a lower gear. It is not happening every day... After releasing the pedal, the speedometer shows correct speed again. This does not happen when accelerating slowly on flat road. It may happen when accelerating slowly on a steep road. I replaced VSS (Vehicle Speed Sensor), but it is the same. What might be the reason? I'm reading live data with an OBD reader and VSS really shows wrong speed when the problem happens. There is no voltage drop when this happens. What other parameters should I check?
Thanks!