loss of power in 93 240

[jkerr240]

ive had some overheating problems lately but ive got all those cleared up now i have one more problem i can figure out. once my car heats up, ill go to push pedal to floor (cars an auto) and it shifts into the lower gear fine but when i get into the higher RPM (4-6K) the temp gauge falls to below cold and i lose power but when it shifts the temp gauge goes back to normal. i cant figuer this out maybe loose ground?? ne ideas would be appreicated thanks

[180fan]

sounds like either the sensor's going out or it needs a cleaning.

[jkerr240]

what needs a cleaning?

[180fan]

cts