When the truck idles the rpms fluctuate up and down occasionally. When I give it a little gas it sometimes stops. And when I'm taking off from a stop and not giving it a lot of gas the Rpms go up and then back down and then up again and then the truck goes
My car has an automatic transmission.
What you are describing sounds like a dirty or failing idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed while adjusting the air/fuel ratio constantly to allow this to happen smoothly. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.
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