My auto/trans on my 92 has been acting up a little lately. I t seems like it drops out of over-drive too soon. This happens at speeds from about 40 to 70 mph. If I am driving around 70 and let of the accelerator it drops into 3rd and then goes back to over-drive. Could this be a serious problem or is there something I can adjust?

 

Sounds like the TPS is out of wack. They are also affected by cold/hot temp to some extent also. do a search on TPS for adjusting info.