RPM jumps up and down, loss of power

Hi, I am new here and i sometime have a hard time with english, sorry for that. Here we go;

I Have a 2008 Escape XLT, V6 Front wheel drive,
Nearly 120k. I use it a lot. I work on the road.

Never had any major issues except transmission after it completely stopped shifting about a year ago. Rebuilt for free at Ford Dealer. Turns out to be on the recall list.

I first noticed some kind of engine kicks idling at a red light after driving in town for a few hours. It feels like it's going to stall but it never does and it is not constent. you can see the rpm quickly droping from about 750 rpm to 500 or so and going right back up. Everything in 1 sec. It will do it 2 or 3 times at every second red light or so. Only does it when the car is hot (30 mins +) and gets worst when driving longer.

Did not worry about it too much but 2 days ago when going up hill i could feel a big power loss. when i pulled the gas a little more the "check engine light blinked for a few seconds, stayed on for another few secs and went off right away. i'd say the truck does half of what he usualy do for the same presure of gas pedal. I tried highway once and the truck didn't like it, it did about the same thing repetely when accelerating and went fine for the rest of the way home.

Any ideas ?

Thank you very much !