mt2500 can you help

[00s10]

2000 s10 auto the problem is the overdrive kicks in and out at highway speeds what i see is the temp gage goes high low put scan tool on it and it shows 40below to normal back and forth new sensor twice could it be bad ground

[Airjer_]

It the circuit goes open it will read -40. So you need to check the iuntegerity of the conector/circuit. I have had more than one connector or wires at the connector fail in the past. The "pigtails" are available from the dealer if needed.

[00s10]

thanks Airjer overdrive works perfect got the pig tail at napa