Check ENGINE light-PLEASE HELP

My check engine light came on the other day. When car warms up and when is idle the rpm will drop from reg 900 to about 600 or sometime even lower than go back up again. I also noticed a loss of power. Also when driving, when the gas pedal is realesed you feel a little jerking. I had this problem before but it went away after couple of days. I really don't know what it could be. I already replaced my spark plugs, and cleaned body throttle without any change. Did ecu test and showed 5 short pulses and 5 long. PLEASE HELP.

the 5 short and 5 long pulses means that there are no errors in the computer. So thats a good thing.

Does it do that??. Why does my rpm fall like that??, why is the ligth on??

Well as your car idles other functions that require different voltages vary. If your engine fan starts up you might notice an the idle drop a little and kick up. This will happen with almost any electrical device in your car. As far as the Check Engine Light(CEL) when you did the diagnostic it gave you the 5 fast and 5 slow? Then it should've turned off. If it comes back on repeat the steps and see what codes it brings up. Until it give you another code, it might have just been a freak thing. I had mine go on the other night, and when I checked the code it gave me 5 and 5. Then the next day it came on with a different number sequence. Sorry I can't be more of help to you.