I have a rover 25 1.4 petrol impression. When I start the engine it runs at just over a 1000rpm then slowly drops down to 600/700rpm when this happens it's seem like it going to stall also when this is happening it won't rev higher then 2000rpm. Also when I'm driving the stalling part kicks in again. I wait for a few minutes then it runs fine. I've looked at the CMP,MAP,. They seem to be working. Do you have any other ideas what it could be. Thank you.
My car has 6500 miles.
My car has a manual transmission.
This may be a sign of a failing idle air control valve. This is a unit that is located on or near your intake manifold that monitors the air intake as it is mixed with fuel prior to being injected into the engine. This valve is controlled by the vehicle's computer which 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. However, when the engine RPM drops below the normal range of 800 RPM (for most cars), it is more than likely that you are dealing with an IAC valve problem. In cases where this valve is clogged or is nearing its replacement age, your vehicle will stall instead of idling after the release of the throttle. I would recommend having an expert from YourMechanic come to your home or place of business to diagnose your vehicle, and replace your idle air control valve.
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