I’m unsure what you mean by “limiting any withholdings.”
If withholdings are the amount held back from your IRA distribution or paycheck that is paid as taxes, then that’s still money your paying in taxes, and still counts towards what can be offset by the EV credit.
If by withholdings you mean money you’re paying into an IRA, and so lowering your taxes for the year, then it is different.
If you do allow your normal withholdings to happen, and then end up with a big EV credit, you’ll get a big tax refund. Sure, it’s an interest free loan to the government, but otherwise not that big of a problem.
If you do not allow your normal withholdings, and then do not get a big EV credit, then you may be in trouble or have penalties.
Also, the EV credit applies for the calendar year the car is delivered. That can be pretty important if you’re planning on delaying a quarterly tax payments or adjusting your W4.
If you’re talking about withholdings as money paid into an IRA, so tax deferred, then my recommendation is set the money aside, and figure out what to do with it after you buy the car, because getting the car in 2022 or 2023 will change which tax year the credit is for.
So, if the car is delivered in 2022, then take the money your were going to put in an IRA, and use it for something else. If the car ends up delivered in 2023, then you still have time to use the money in a 2022 IRA, because you can do that until the tax deadline in April