Q: RPM problems

Hi, thanks for writing in. This may be related to couple of things such as a vacuum leak or potentially an improperly adjusted throttle plate screw. When a vacuum leak is present in an engine, it can cause an imbalance in the air/fuel mixture which can cause the engine to race or surge at a higher RPM than normal due to the excess air flow. The same effect is also similarly true when the throttle plate is incorrectly adjusted. This is a plate inside the throttle body that remains slightly open to let just the right amount of air in at idle to maintain the proper air/fuel mixture. When this is incorrectly adjusted allowing too much air in, this will also cause an imbalance in air/fuel mixture, again causing the motor to race or surge at a higher RPM. I would suggest having an expert from YourMechanic come to your home to diagnose and correct your high idle issue.