My starter went out, so I had a mechanic take apart the entire engine to get to the starter below it. When it was replaced and all put back together, my car's speed will only get up to 35 MPH.
This sounds to me like something was done incorrectly during the repair. Engines now have many sensors that all feed back information to the many computers of the vehicle. If any sensors were left unplugged, that is likely your issue. I would recommend having the mechanic that did the repair take another look at your vehicle to ensure that their repair was done properly. If anything is found to be incorrect, the mechanic should be able to fix it for you under warranty. You can also have an inspection from a certified mechanic, such as one from YourMechanic, to make sure that you have the proper diagnosis.
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