I need some help on a 95 Camry 4 cylinder 2.2L.

Lately, I've notice some strange behavior from the car.

When the car is started well, the RPM's shoot up high and stay a little bit above 1000. This is when the car feels really smooth and the acceleration is very powerful and nice. I also notice its a lot more fuel efficient as well.

Sometimes, on a bad start, it idles really rough until I switch it on Drive and drive for a little bit.

Most of the time, after a while when the car is considered warmed up, the RPM's in idle go below 1000 and the car starts to feel unresponsive and less powerful. Pretty much the opposite to on a good start.

Is this battery related? IAC valve? Camshafts? (All guesses)

Any kind of advice or help is very much appreciated!

FYI, I do not know much about cars but I am currently learning.

Please use simple terms.


Thank you.