question on idle -

i noticed a strange behaviour,

the engine idles around 600 RPM, as evidenced by internal tests, all normal...

then the idle spikes briefly to about 800 and then falls back to 600

this happens so fast that the test function registers this for a brief second

this happens even when the car is in gear, and say, if i am backing up, with a foot on the brake, the idle racing would feel as if i am using one foot on brakes and the other foot on the gas simultaneously... again, for a brief moment... i can reassure you, my foot is NOT that wide to stay on the brake pedal and slip onto gas at the same time...

I cleaned the MAF (mass air flow sensor) with MAF cleaner, the issue is still there. I have K&N air filter coming in sometime today, will replace it as soon as it arrives...

Any suggestions?

No engine light but I have not connected the comp to see if there are any codes and to read the live data off the engine... I need to revive my XP machine to do just that...