What causes engine idle surge?
If an engine is not getting enough fuel (this is called “running lean”), due to fuel pressure (regulated by the fuel pump and regulator), restricted fuel injectors, a vacuum leak or really anything that throws off the fuel mixture going in to the engine, this can cause the surge.
Can a bad O2 sensor cause surging?
Oxygen sensors are among the most interesting and important sensors on your engine. Surging is among the many problems a failing O2 sensor can cause, but it isn’t the only one.
Can a dirty air filter cause surging?
A clogged or obstructed air filter can cause surging at idle, and foreign objects can enter the filter housing at any time. Any debris in the filter or housing might restrict air flow to the engine enough to affect idle speeds.
What should the idle speed be on a Toyota pickup?
The adjustment setting should be one to two turns out from full bottom but use the appropriate service manual to properly set the air bypass screw. If someone has used the air bypass screw to turn up the idle speed, the idle can be too high and also cause the engine to surge.
What causes an engine to surge during a tune up?
Step 2 – An engine’s tune up is a regularly scheduled service, when this service is neglected it can cause the engine to surge. Learn more Step 3 – If a fuel pump or regulator is failing is can cause an unsteady volume or pressure for the fuel system causing the engine to surge. Learn more
What causes engine to surge at high idle speed?
If someone has used the air bypass screw to turn up the idle speed, the idle can be too high and also cause the engine to surge. Customer Concern: High surging idle up to 2000 RPM when hot.
Why does my Toyota pickup engine lower rpm?
Engine coolant should heat the wax pellet as the engine is running causing the wax pellet to expand and block the air passage to lower the RPM as the engine warms up. The auxiliary air control valve should be closed when hot and is not designed to keep adding air hot.