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Discussion Starter · #1 ·
Alright first off i want to start by giving the run down. The car has 220k on it and 99% of those miles have been interstate. Oil gets changed every 3000- 3500 miles, air filter is new. For the past few months, since the beginning of summer my car has been idling at 400 rpm, sometimes it fluctuates up to 600 or so and falls back down, it doesn't necessarily feel like a miss, more of just a rev hang of sorts. It does it most on first start up/cold start. The car doesn't lack in power and i still get 30+mpg easily. A month or so ago i got a fault code for an evap fault.....p0449 i believe it was, the code went away after i removed and reinstalled the gas cap. What problems like this have people ran into?


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I would add a bottle of Techron Fuel System Cleaner to the gas tank according to label directions. I would also clean the inside of the throttle body with throttle body cleaner. The butterfly valve blade may have dirt on the ends and around the inside of the throttle bore, not allowing enough air to bypass the blade.

The evap system code may indicate a sticking or defective evaporative solenoid valve which opens at a certain speed to purge the evap system fumes held in the charcoal canister. If the valve is open (even partially) at idle, it will cause a drop in idle speed and an erratic idle.
 

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Discussion Starter · #5 ·
I would add a bottle of Techron Fuel System Cleaner to the gas tank according to label directions. I would also clean the inside of the throttle body with throttle body cleaner. The butterfly valve blade may have dirt on the ends and around the inside of the throttle bore, not allowing enough air to bypass the blade.



The evap system code may indicate a sticking or defective evaporative solenoid valve which opens at a certain speed to purge the evap system fumes held in the charcoal canister. If the valve is open (even partially) at idle, it will cause a drop in idle speed and an erratic idle.


The evap code went away when i repositioned the fuel cap. I didn't think much about it after. I have an evap solenoid sitting at home that i can always throw on.


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