2009 Toyota Camry

My 2009 Toyota Camry. I have to crank it over
several times for several seconds while also
pressing on the gas just to get it started. After I get
it started, the RPM is already up above the 2 and
then it slowly comes down after the car has been
running for about 5min then it starts to loose RPM
pressure and goes out. But if I press in the gas it
will stay on. Now when I put it into drive when I
press on the gas it hesitates then it get
acceleration and this is every time I press on the
gas. While also sitting at an intersection the car
looses power almost immediately,where I have to
press on the gas to keep it going or pull over put
the car in Park and continue to press on the gas
until I can go through the light just so the car
doesn't cut off. It also looses acceleration and
power when I turn onto another street. The car also
has lost power while I drove but it started back up.
I replaced the MAF and the fuel pump and strainer.
Could my O2 sensor cause these problems or
could it be the catalytic converter??