car revs without pressing accelerator pedal

2008 TOYOTA YARIS
71,000 MILES • 1.0L • FWD • MANUAL
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VALJEANLK
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Hi all,
Sorry to post another question here. I am getting mad with my second hand car. You better never buy a second hand car like me. :(

Today afternoon, I drove my car for two and half miles. Suddenly, I felt something was not right, the car revved up and down and up and down itself without my foot. When I stopped the car for checking, the revolution was up and down between 900-1500 at idling. It was happened for about five minutes. I checked the accelerator pedal for stuck but nothing. Then, I drove the car to my home at very low speed and now the car is running normally.

But, I feel very unsafe and do not know what it is. I want to lean what is the problem before bringing the car to a mechanics for checking, as they will charge me very costly here in Ireland. I do not have much money :(.

Can you guess what problem caused my car revving up and down and up and down itself without my foot?

Thanks,
Jan 14, 2017 at 10:42 AM
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SATURNTECH9
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That can be a vacuum leak sensor etc. have you scanned the car for codes yet?
Jan 14, 2017 at 12:38 PM
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VALJEANLK
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Hi Saturntech9,
I have just scanned, and no code was detected. No warning light shows. So, do you think I should check for the vacuum leak, right?
Jan 14, 2017 at 3:33 PM
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SATURNTECH9
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Yes you can look for a vacuum leak and see what you find.Also you would have to see what was happening on a scan tool live data wise while it was acting up.I would start by looking for a vacuum leak.Even a bad coolant temp sensor could cause erratic rpms.
Jan 15, 2017 at 1:54 AM