Mechanics

LOW IDLE & SHAKING ONCE WARM

2002 Toyota MR2

Shakes or Wobbles problem
2002 Toyota MR2 4 cyl Two Wheel Drive Manual 100200 miles

My cars starts just fine, but as soon as it reaches normal operating temperature, the idle drops to about 500rpm (from about 1100rpm), and the car starts shaking. This happens only at a stop, but it happens as soon as I stop. This is a new problem that started suddenly. There are no codes in the computer, but the oxygen sensors were sending different voltages, so I replaced the two oxygen sensors in the header (did not change post-cat sensor). Now they read nearly identical, but I still have the idle problem. Toyota claims it is the computer mapping, and that I have always had this problem (and that it is not a problem), but I would have noticed this in the first 100,000MI if it was there before. I tightened the throttle cable so that it cannot go to idle, but I would still like to find the cause of the problem.
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KillerBug
August 21, 2008.



Hi KillerBug,

You should not use the throttle cable to control the idling speed. It would make idling very erractic.

I would suggest giving the throttle body a good cleanup with carb cleaner. Some clogging of the air passages in the throttle body and IAC has caused restricted air flow and thus the low idling rpm.

KHLow2008
Aug 24, 2008.
Thanks for the advice, it started me on the correct fix. I removed & cleaned the throttlebody, and replaced the gaskets, but it did not help. I then replaced the PCV valve, that smoothed out the idle. Then I turned the idle screw in 1/2 turn so it does not stumble after releasing the throttle (I think the Toyota mechanics messed with this). Everything seems to be fine now.

Thanks Again!

Tiny
KillerBug
Oct 20, 2008.