OVERDRIVE on 1995 Buick Century

AFTER 10 MINUTES DRIVING MY CAR, THE OVERDRIVE DOES NOT WORK AND THE CAR LOOSES POWER. THANKS FOR YOUR ANSWER.

1 answer 2 comments
Need more info. How do you know that the trans doesn't go into overdrive? is there a check engine light on? Have you had a fuel pressure and volume test done?
THANKS FOR ANSWERING. BECAUSE WHEN I TRY TO PASS ANOTHER CAR, THERE IS NOT RESPONSE WHEN I PRESS DOWN THE ACELERATOR; YES, SOME TIMES (ALMOST ALWAYS) THE CHECK ENGINE LIGHT IS ON; NO, I HAVEN´T DONE THE FUEL PRESSURE AND VOLUME TEST DONE.
Need trouble codes to help you.