Have Toyota Questions? Ask a Mechanic for Answers ASAP
Hello. My name is ***** ***** I will be assisting you today. The issue that you have are is likely going to be do to a vacuum leak or a misfiring cylinder. Even though the check engine light is not on, you should still have the vehicle scanned for codes. I have seen many vehicles without a light still have codes to retrieve. This should be the first step. Check for vacuum leaks. What you need to do to inspect for this is check all of the vacuum hoses, including the air filter box. Also, you should check the air filter. If you can't visibly see a vacuum leak, then start the engine, while someone revs it enough to stay running. Listen for escaping air. If there is a leak, this will help you pinpoint it. Harder to find leaks can be located with a smoke machine.... To check for misfiring cylinders, you will need to perform a power balance test. If there is a misfire, then you will be able to locate the cylinder and then the cause. These two causes are the most likely issues to your problem.
If you require more information on this issue and/or are not satisfied, let me know, please, and I will attempt to assist you further on this. I hope this information points you in the right direction. If you have any further questions or concerns on this issue, feel free to ask. If you are satisfied, and have found this information helpful, a positive rating would be greatly appreciated. Thank you.