either your plug or plug lead is faulty replace both
Acceleration Cable broken broken, you dump!
Adjust the idle screw.
Nothing funny here....bad clutch disc.
zyou tps might be bad
On my Chevy truck it idles high when its low on antifreeze but if its not that more than likely its usually a vacuum line loose or cracked. good luck.
If the engine idles and revs up okay in neutral, it is likely the torque converter clutch lock up solenoid.
why does my 4.75 BRIGGS & STRATTON lawnmower engine idles high and low when cutting my grass
Need a little more info. What Model and year of the vehicle?
Needs a Tune up
Year, make and model would help.
Run a compression test to verify the condition of the engine.
A) It needs to be serviced. B) An animal in your trunk is uneasy when the engine idles.