Q: Rough Idle Solutions

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My truck was running beautifully and I had to switch the clutch master cylinder recently, but the idle is so rough that now my truck is dying while I'm driving as we as at a stop because it drops so low. If I keep rpms up at a stop I can keep it from dying sometimes but it's also shaking horribly when at a stop. I have been told that if I clean the mav and iacv that might help and if not to do the tb next. My question is should I just get the iacv to make it a guarantee or is it possibly something totally different all together?

My car has 166000 miles.
My car has a manual transmission.

Hi There, Although there is no way to guarantee what the cause may be, what you are describing sounds much like what happens when the idle air control valve (IAC) is not working properly. 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. When the engine RPM drops below the normal range of about ~800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve.

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