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Toyota Repair/Rough idle only in gear


Hi Ted,

I have a 97 Celica with 180k on it. I am the original owner. The car runs smooth while in park or neutral but vibrates while in Drive. I only notice it while stopped. The motor mounts were replaced last year when it failed inspection so I don't believe that's the issue. I notice that it idles in drive around 600 Rpm and goes up to about 750 in park or neutral. Could the idle just need adjustment or is that just cheating it and hidden a problem?

Thank you,


The idle is not adjustable on this engine it is controlled by the idle air control valve if the idle is too low it can cause a vibration, it should be around 800 rpm, if the vibration is there at that rpm it should be checked for any contact between the engine, transmission and exhaust system and the body. If the idle is too low, around 500 or less the idle air control valve may need to be replaced. The idle of 600 rpm is a little on the low side, if the vibration stops by applying throttle to 750 rpm in gear the problem is the IAC valve.

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Ted Ritter


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 more ten years an have answered over 16,000 questions helping Toyota owners with their problems and save thousands of dollars without any compensation, some of my answers are published on many other websites including google and various automotive forums. DONATIONS ARE VERY MUCH APPRECIATED, IF YOU HAVE RECIEVED HELPFUL INFORMATION PLEASE MAKE A DONATION. AS OF TODAY (JULY 22, 2014) ALL REQUESTED GRAPHICS, ILLUSTRATIONS, DIAGRAMS, PHOTOS, WILL REQUIRE THE MINUMUM DONATION UP FRONT.


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