Q: Cat won't go over 20 and when idle it sputters like it is going to cut off

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Car will not go over 20 mph and when it is idle it sputters like it is going to cut off. When in motion the rpms will go up but the speed won't
My car has an automatic transmission.

Hi Samantha. Thanks for contacting us tonight. In most cases, a lack of acceleration like you’ve described is caused by some sort of fuel restriction. Either a fuel injector (or several) are clogged with excessive carbon deposits (or debris), or a mass air flow sensor is having difficulty correctly mixing air to fuel. Other possible sources could include a damaged throttle body, defective or clogged fuel pump (fuel filters) and even a failing or clogged catalytic converter. Since there are so many possible sources, it’s best to have a professional mechanic complete an onsite inspection to help the correctly diagnose this issue.

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