Good morning! The answer is yes!

you can pay online, in one of two ways. The first way is to get set up on what’s called Electronic Federal Tax Payment System (EFTPS.gov). You create an account there and then make payments. That is how we paid our back taxes for two years (which we paid off earlier this year, yay!) The good news is that service is free. The bad news is, you may not have enough time to get your account set up. Being the federal gov, there are certain hoops you have to jump through (getting a PIN from them, for example). It’s a great system if you have to make a series of payments over time. For a single payment like yours, particularly if it’s coming due soon, it might not be worth the hassle.
A second option is to go directly to the IRS.gov website, and click on the Pay Your Tax Bill which is one of the main options across the top of the page. That will take you to another IRS page which gives you a variety of both free and fee-for-service options. The fees are generally quite low, on the order of less than $5.00. You can go to that page and start to walk through some of the options and figure out which option suits you.
Sorry to hear about the car. We’re finally closing in on being done with my truck’s conversion away from computer emissions control (many of which were failing) back to mechanical emissions control. The estimated bill to do the conversion was between $1000 – $1500, but doing it ourselves so far it’s been less than $500. The catch is that we could have been done months ago if we’d just paid someone. I’ve had to really bone up on my automotive electrical knowledge to tackle this project. Nice to almost be done, but there’s always some price to be paid in either time, effort or cold hard cash. I hope you come up with a solution that works for you.