Honda idle problem......help!

ok so i bought a used 2001 honda crv automatic on craigslist and i had it for six months
and it was all good then started servicing all i did was oil change and transmission fluid
change only

Then it went down hill from there. first the check engine light came on and it read TPS
sensor was malfunctioning so i changed it and check engine light didn't go away. My car
started to rev up too 4000 rpm in order to switch into 2nd gear and when i put it on drive it
jerks hard. Then a friend and i took off and cleaned the whole throttle body and Idle air
control valve. boom the problem was gone it was changing gears when it was supposed
to and everything was back to normal, even the check engine light went off by itself.

then exactly one month later the exact same problem came back rev 4000 rpm to change
into 2nd gear and jerking when placing on drive. a mechanic suggested i use a fuel
system cleaner because sometime fuel injectors get dirty. so i used a fuel system cleaner
and again boom the problem was gone it was back to normal and check engine light
came off.

then again exactly or almost a month later the problem returned yet again, like always
one day its all normal and the next day check engine light comes on and start acting the
same. this time i replaced the throttle body with new sensors included both TPS and MAF
and yet again the problem was gone but it only lasted a month.

the only time the problem didn't go away was when i replaced the idle control valve.

then i thought that something was making my throttle body dirty so i disconnected the
PCV system, added a new PCV valve and i cleaned the throttle body again and adjusted
the fast air control valve and problem was gone for a month. and now it does the same.

im all out of ideas, What can it be!?help.... thinking about replacing the ECU