‘98 Acura 3.0 CL knocking in front right side when coming to a stop as well as strange/delayed shifting

I’ve had my 1998 Acura CL 3.0 fwd for about a year and have put about 13,000 on it with no issue, except the engine light coming on now and again for clogged exhaust, so in September I decided to put some work into the car, as it still drives like the high performance vehicle it was previously sold as. I got the all the brakes, roaders, bearings, pads, and the exhaust replaced. Not even a month later, a large metal piece on the bottom of my car was basically ripped off by a messed up speed bump in Chicago. It is almost an elongated oval shape with “gills” on either side in spots that are clearly for ventilation, so I’m assuming part of the exhaust as it was located directly in the center of the middle of the car, just a bit towards the front. Never got it replaced(it’s still in my trunk). Now, beginning of December, as I’m coming to a stop, I hear a knocking in the front on the right hand side of the car. I asked my passenger if he could also feel anything under his feet where the noise happened, and he said yes. I’ve also noticed lately that the car seems to stay stuck in gear, both when I hit the brakes and gas. I’m bringing it in for an oil change today, and I’m going very close to the house, but I’m pretty worried about what this may be. Hopefully I can fix it in my own!! Thank you so much in advance for any help that anyone can provide!!