Oil Change with filter

There are two crankshaft seals, front and rear. The rear seal would be expensive to repair because you must remove transmission to get to it.
The front seal is a lot less expensive to change, because it is easier to get to.

Find out where the leak is coming from, if rear (or front) seal it will eventually have to be changed.

Bad oil leaks will not only cost you oil, but the oil leak MAY work its way to the exhaust system and the POSSIBILITY of fire is real.

Take the car to a trusted ASE certified mechanic and have them isolate the location of the leak.
It could also be an oil pan, oil pressure sender etc.

You have to mail other members. Try cleaning your throttle plate on both sides and iac hole with choke cleaner then check fuel pressure with a gauge auto parts rent it.

If the car has been sitting for some time, open the gas cap and smell the gas, if it has a varnish smell then would suggest fuel stabilizer and cleaner. This will help clean the fuel system. When a cra sits for a long time the gas will start to go bad, that is the varnish smell. If the car runs ok then would just put the cleaner and new gas in it. Check all the rubber hoses, sometimes they dry rot and get brittle. Make sure all the fluids are checked and filled.