Dear Tom and Ray:

I have a well-maintained 1989 Toyota Camry four cylinder with 160,000 miles. The problem is the throttle body seems to get dirty, causing the throttle to stick. It has to be cleaned and lubricated every month or so to keep it from sticking. The dealer now recommends a new throttle body (a $700 part). Visually, to my untrained eye, there doesn't appear to be anything wrong with the old one. What would you recommend? -- Bob

Tom: The dirt isn't what's making it stick, Bob. And in fact, cleaning and lubricating it is probably making it worse, because the grease they use attracts dirt.

Ray: What's making it stick is that the steel throttle plate has worn a groove in the aluminum throttle body, and the throttle plate is getting hung up in that groove.

Tom: That plate opens and closes every time you move the gas pedal. So you can imagine that it gets a lot of wear and tear over 160,000 miles. And replacing the throttle body certainly would solve the problem.

Ray: But before you do that, try one more inexpensive solution. Have your mechanic try turning the curb idle speed screw to crack the throttle plate open slightly. That way, its "resting position" will be slightly above the place where the groove has been created.

Tom: Then you compensate for the higher idle by turning in the "air bleed screw" to lower the idle back to where it belongs. Then all you have to do is check the emissions to be sure they're in spec (assuming you live in one of those civilized states that checks emissions).

Ray: If the groove is bad enough, this trick may not work, but it's always worked for us, and we've never had to replace a Camry throttle body. Good luck, Bob.

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© 1999 by Tom and Ray Magliozzi and Doug Berman Distributed by King Features Syndicate, Inc.

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