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Toyota Repair/air valve

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Expert: Ted Ritter - 5/8/2004


Question
I have a 1990 4 runner V6, my problem is bad gas milage and performance ( can not get above 80 mph). I went thru the haynes repair manual cks for the fuel injection system.When I checked the air valve, It tells me to adjust the idle screw all the way in while the engine is cold and the rpm should drop , after it has warmed up there should be no drop in rpm. According to this check my air valve is bad. My question is where is the air valve? the manaul I have shows a pic but Ihave not been able to locate any valve with coolant hoses going into it. Thanks Ron

Answer
The rpm will change when the adjustment screw is turned when the engine is warmed up at idle, it has no effect when the engine is cold and at fast idle and has nothing to do with driveability or loss of power, I don't know what air valve the haynes manual is referring to.
The problem is elsewhere, check for a possible engine misfire, check the basic engine timing, these engines had headgasket problems, so you may want to check for that possibility.  

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Ted Ritter

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I have more than 28 years experience as toyota technician, I will be able to answer most questions related to the Toyota product line up to the present year models,I am located in the US but welcome questions from other regions of the world. When asking a question please provide specific information: year,model, engine,transmission information. Provide as much information as possible including a brief repair history if possible. I have been a volunteer here for almost ten years an have answered over 16,000 questions helping Toyota owners with their problems without any compensation, some of my answers are published on many other websites via google and other search engines. AllExperts recently added a new feature which allows questioners to donate to experts on the site, any amount of donation is very much appreciated, to make a donation just click on the DONATE button.

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Toyota technician since 1979,expert in electrical systems,OBD systems,engine repair, driveability problems,EFI systems,ASE certified,Toyota master technician.
Certified Hybrid Vehicle technician.

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Toyota master technician, ASE certified in eight catagories, Hybrid vehicle certified. Toyota technical training: Engine Automatic transmission Manual transmission Drivetrain Electrical systems Brakes and chassis Air conditioning Engine performance and diagnostics Hybrid systems

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