stalling, poor idling, low compression, poor acceleration

I bought a 2003 325ci e46 with 82,000 a week ago and ever since I got it home it's been stalling randomly when I start it, shuttering when it idles, getting stuck at 2500 RPMs while shaking, stalling at long lights, problems accelerating and is overall sluggish.

I put it on a diagnostic and I got these codes

P0313 misfire detected with low fuel

P0300 random multiple misfire detected

P1346 no dtc definition found

P1350 Upstream oxygen sensor, circuit malfunction

P1083 no dtc definition found

P1085

P1344

P0171 Bank 1 system too lien

P0174 bank 2 system too lien

P0313 misfire detected with low fuel

Catalyst monitor inconclusive

Random multiple misfires



I did some research and I found a thread that said these types of errors are commonly associated with vacuum leaks, spark plug issues and fuel pump/filter problems. I left the battery off overnight.



so I replaced the spark plugs today, which were well overdue and in pretty poor condition. the last spark plug had oil on it. I'm told by my mechanic friend that could be caused by bad piston rings, I'm going to have him check that out.



I removed the fuel filter and I have ordered a new one following a guide I found on this forum.



after replacing the spark plugs the idle was a rough as ever but the revving sounded sharper.



I feel like I likely still have a vacuum leak but I don't know how to find it and I don't know what else all these errors are caused by.



the hope of this thread is that someone will be able to look at the codes and know the common cause of all of them in conjunction and it will save me the trouble of replacing every hose not knowing when I have fixed the problem



I would appreciate any help, videos or advice.