AboutTed Ritter Expertise I have more than 26 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 specialize in difficult to diagnose problems but when posting a question please keep in mind that some situations require the used of special test equipment and diagnostic procedures especially as the newer models become more technologically advanced, so without actually having the car on hand I may only be able to try to steer you in the right direction and in some cases may have to refer you to the toyota dealer but at least you will know what you may be dealing with. Please don't hesitate to ask any questions, I will have an answer for you in most cases. When posting a question keep in mind that I reside in the US, although I get questions from all over the world I may not have an answer for models that are not sold in the US, I will do a reasonable search to try to match your model to the US model,please refrain from asking about diesel powered vehicles, I have no information for them. In most cases I will not answer questions about major modifications of OEM components, engine swapping or aftermarket products,please post a question not a statement, please provide enough basic information such as year, model, what engine and if anything has already been done to fix the problem, the more information I get the more I can help without having to ask you more questions.
Experience 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.
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.
