Hello and thank you for using JustAnswer. My name in Nelson, and I have been a licensed automotive technician for over 12 years now and currently working at a Toyota dealership.
I have looked into this problem you are having and I have found that there are a few common problems that can cause this. One is being a clogged catalytic converter, and if you say that it is burning oil at that rate, there is a possibility that the converter is clogged with oil. However any time I have found that to be the problem I have always suggested replacing the converter and also the engine with a used engine with less miles on it. If the car is burning oil at that rate it will continue to clog the converter with oil, and washing out the converter will not help, at least not for very long.
but there are also 2 other very common problems with a loss of power. It is common for the alternator to fail and to begin over charging. If the charging system voltage is above approximately 15 volts the Engine Control Module shuts the throttle down without setting a code
And lastly the 3rd common problem is a failure with the the electronic throttle body, but this however will set codes in the computer and the check engine light should be on.
I hope that I was able to help answer your question. If you have any questions please don’t hesitate to ask.
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