my toyota corolla xli 2007 is having rpm dropping problem. Its a manual car. When i pick up from first gear and give it a speed through speed padel it instantly drops the rpm then return back to normal level. Its mostly happening with air conditioner. We tried every possible thing for this like coils checking, changing of plugs, injectors cleaning, throttle body cleaning etc. We also have gone through with car computer scanner. Its all clear and not giving any sort of sensor or other ecm related fault. I am confused about the next step to sort out this problem. Please help me out