2005 Ford Focus losing power

I have a 2005 Ford Focus. It has recently begun losing power. The RPMs will race while the speed steadily drops (especially on hills but it’s started doing it on lesser inclines). It’s been accompanied at times by my car shifting hard and the overdrive off light flashing orange until I pull over and turn it off. When I start it again the light clears. There are no other warning lights. I’ve taken it to my mechanic twice. He’s serviced the transmission, replaced the spark plugs and the fuel filter. He’s run the diagnostics and nothing is showing up. And of course when he test drove it he couldn’t get it to act up. Any thoughts on what I should have someone look at next?

I would be looking for a local (Not a chain operation) transmission shop.

How many miles on your Focus and when was the last time you changed the transmission fluid and was the filter cleaned at that time?

122,000. Had my transmission fluid and filter changed about 3 weeks ago.

How many times has the transmission been serviced prior to this?