Hi new member to the club

I'm in need of help with my 93 sc400 ASAP!
I don't know how to work on these cars but long story short I welded my diff (drift car)the car ran fine after i tested it but today while doing doing donuts the car stalled (mid drift) so I drove it back home turned it off then on and it has a funny idle now I changed the alternator when I first bought the car (old one was covered in ps fluid) so I honestly don't know what could be the problem maybe a bad ps pump ??*♂️🤦🏾*♂️🤦🏾*♂️🤦🏾*♂️🤦🏾*♂️🤦🏾*♂️
If anybody can give any insight on this is really appreciate I have a big event coming in a week (sorry if I don't make any sense)