Your overdrive keeps kicking in and out what controls this on a 1994 ford van E150?

In a 1994 Ford E150 van, the overdrive feature is controlled primarily by the transmission control module (TCM) and the throttle position sensor. If your overdrive keeps kicking in and out, it could indicate an issue with the TCM, a malfunctioning throttle position sensor, or a problem with the Transmission Fluid level or condition. Additionally, a faulty vehicle speed sensor may also affect the overdrive operation. It's advisable to have the vehicle diagnosed by a professional to identify the exact cause.