I replaced my slave cylinder on my 2006 pt cruiser and had a lot of air in the system but now its like when I put it in gear and step on the gas I dont move either something isnis something not engagi

see link for manual
https://workshop-manuals.com/chrysler

O2 sensor has nothing to do with engine overheating. Are you losing coolant? Did you bleed all the air out of the cooling system after replacing radiator? Have you checked the coolant for exhaust gas byproducts? You may have a bad head gasket, or a cracked block/head if you ran the car for an extended period while overheated.

Try pumping the clutch a while, sounds like trapped air. There hard to bleed . Look up a bleeding procedure .it may show you some thing different to do

Sometimes the rod on the slave cylinder by the transmission is adjustable, and you can get more travel. Have somebody pump the clutch pedal while you watch the slave cylinder rod moving.

When you replace a slave or master cylinder you have to do a bleed of the master cylinder. It is called a bench bleed. I am sure there is a lot of air in the system.

The Clutch Master Cylinder or the Clutch Slave Cylinder has a leak. From under the dashboard, located the Clutch Master Cyliner Boot and pry one side open. If hydraulic fluid drips out, the piston seal(s) in the cylinder are worn. You'll need to replace the cylinder.

It may be that the throwout bearing is lightly contacting the clutch assembly even when not in use. Check to see if there is an adjustment for the stroke of the clutch slave cylinder at the transmission. It may be pushing the throwout bearing into the rotating clutch assembly.

is the clutch power assisted(vacuum)?if so couldvery well have some bearing on what is happening.I WILL TELL YOU A STOREY.A couple of months ago I changed the clutch master cyl. on my land cruiser and because I do all my own work still I didnot obey the golden rule..3days later i changed the slave cyl...l again did not obay the golden rule...... 2 days later iagain pulled the master cyl off cleaned it all out, but this time I OBEYED THE GOLDEN RULE,WHICH IS::always change the brake fluid when ever you change amaster cylinder either brake or clutch or when I was doing work for other people,if the brakes were worked on or the clutch you drained the sytem and relaced the fluid...ANY COMMERCIAL WORKSHOP THAT DOES NOT DO THIS IS GOING TO HAVE COMEBACKS ..it may only be 5or10% but for a $5container of fluid it isn` t worth the chance I was in that5 or 10 % are you? that is true,not more than 3 months ago give it some thought ....................

OK, if it's a cluth probelm then you either need a new clutch, or it's a problem with the slave cylinder. I've even heard if as simple a problem as the bolts holding the slave clynider coming loose, so when you press the clutch, the slave actually moves. If you're having troubles getting it into gear (metal on metal) your shift linkage bushings could be worn. There are 2 on the shifter end, and 2 on the transmission end. I recommend replacing them with a more solid bushing from ****** Racing (www.boogerracing.com) that will give a much more confident feel than the stock rubber bushings.