mitsubishi montero limited 2003 clean and in excellent condition!

The original question was supposed to be this, The car starts fine but when Idling the motor slows down and speeds back up to it's original rev'S IT ALSO DOES THIS WHILE DRIVING . I only notice this happening when excelerating from a very slow speed I can feel a slight surge  which as i reac around 20 mi/hr it becomes unperseptible and the enging runs excellent and shifts its variouse gears smooth and even with out surge . I reiterate the surge is inperceptible it does not seem to effect the engins performance , I suspect it is consuming more fuel and am afraid that this will send the car into safe mode ! I was looking at some typical similar complaints ad the different trouble shoots , one being the cleaniinig of are intakes and mass air sensor problems all the way to torq coverter sensors ect... including the dishartining replys from certain delear and shop mechanics . that the proble was a mistery or sufficiently difficult to diagnos even using the electronic scaning computer and its codes.   Are there any real mechanic tech experts  reading this that might care to comment , your imput would be much appriciated and use as a guide thru the jungle of electronics switches and sensors relays and stored old memory codes that need to be erased to a leaking vacum or fuel pump ect...!  thanks !