Wiil not go above 15 MPH?

Hello, is the Check Engine light on? It sounds like you may have either a fuel pressure/volume issue, or a clogged Catalytic Converter.
To do a fuel pressure test on these vehicles, they want you to remove the fuel pressure damper from the Fuel rail and screw in a fuel gauge at that point. I'll post the instructions. Since this test takes a lot more time, you can try removing one of the front Oxygen sensors and see if the vehicle will rev any higher, if the Converter is clogged removing one of the front oxygen sensors will relieve the exhaust pressure that is building up. It will be loud, but this is the location for doing a back pressure test because it is before the Converter.
With the oxygen sensor out, you should notice a difference right away. The sensor will probably be covered in soot as well. So will the spark plugs. Here are a couple of guides to help.

Also do you notice any noise from the exhaust, or any rotten egg smell? Those are also sign of a failed Catalytic Converter.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Glad to hear you got it repaired. You may want to make sure there are no misfiring cylinders or over fueling issues. Thats what will usually cause a Converter to melt down and clog up the exhaust. Checking some live data with a scan tool can tell you how much the engine computer is compensating for any conditions. The Long Term and Short-Term Fuel trims will tell you if the engine is running rich or lean. Positive fuel trim numbers mean the engine computer is adding fuel to the air/fuel mixture for some reason, i.e. a vacuum leak, misfiring cylinders, incorrect timing, incorrect oxygen sensor readings, etc. Negative fuel trim numbers mean the engine computer is taking fuel away. And I know Converters are very expensive. You don't want the new one to go bad prematurely. Hope this helps some.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Only if the hole was very close to the oxygen sensor that is behind the Converter, there is an oxygen sensor in front of the converter and one behind, they both work together to provide information to the engine computer for emissions purposes, if the rear oxygen sensor was reading oxygen that was coming in from outside the exhaust, this will fool the computer into thinking the exhaust is lean and therefore enrich the mixture incorrectly. So that's a possibility.