Hello, I have all the vacuum diagrams pulled up for you, but have you checked to see if there is any carbon build up on the edges of the throttle plates, another possibility is the Mass Air flow sensor needs to be cleaned, the small resistor inside the MAF eventually gets dirty and the sensor will under report air flow causing a rough idle, I will put up a guide for cleaning the MAF as well. Auto parts stores sell Mass Air flow cleaner designed for that sensor specifically.
The 1st diagram is the vacuum hoses in the engine compartment, the intake manifold I colored in orange just to identify it, the 2nd diagram is the Evap vapor management system which pulls fuel vapor from the gas tank and burns it in the engine to keep emissions down.
You can try temporarily blocking off the Purge valve and see if it causes the idle to smooth out.
The 3rd diagram is if your vehicle has vacuum controlled HVAC heating system. The HVAC controls divert vacuum from the engine to different solenoids in the dash to move the different mode doors for the vents and temperature controls. So, if you have any of the vents that don't divert to the floor or defrost, it's possible for there to be vacuum leaks in the dash that affect the engine.
Has the check engine light been on at any time?
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Wednesday, October 18th, 2023 AT 4:37 PM