Q: Car runs, then stalls from passlock, then goes again, sometime turning off the car.

So I changed my spark plugs on the left side, and replaced both valve cover gaskets. After putting everything back together and hooking the battery back up, my car wouldn't turn over. Said passlock wasn't letting me start it so I ran through the passlock key re-learn process, and started it up afterwards! Got down the road and my car stalls out and does. So I turned it off, turned it back on and it ran again! For maybe another 100 yards anyway. Passlock again, so I floored it, and going 105 down the highway it would stall out and I'd coast, then keeping my foot on the gas, it started going again and this process repeated all the way home. It still is doing the same thing and I don't know what to do now. I looked into bypassing the security system but wanted to get some more professional opinion on it. Thank you! Much appreciated!

My car has 195600 miles.
My car has an automatic transmission.