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I got a car (Toyota Yaris 2008 1.8L engine VVT) for diagnosis. The Owner complaints that the car has very poor mpg compared to before.
I used Gscan2 scanner, there was no code. I closely looked at LTFT and STFT both on idle and driving. It was in good range of 3 - 6 of both ST and LT.
I checked spark plugs, injectors, Coil, maf (clean). I found that the PCV had failed stuck open. After replacing the pcv, the owner came back with complaining nothing has changed in MPG.
how to check for evap and egr? I have not diagnosed these system.
If this car comes to you for poor MPG, what is your method for diagnosing this condition???
I always start with what was your mpg before and what is it now (most people have never figured out what there mpg is before they complain about it )(so I have them till tank and check mileage and report back and about half find out there right on track for what there vehicle should get....) from there your basic checks , carbon cleaning and intake cleaning help with a couple mpg if everything else checks out but it's important to know your mpg before you start
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