Misfire Codes P0300 & P0301 2.8L

[2.7taudi]

scanned my car today and got some misfire codes: 2001 a6 2.8 FWD 97k 2 Faults Found: 16684 - Shareware Version. To Decode all DTCs P0300 - 35-10 - Please Register/Activate - Intermittent 16689 - Shareware Version. To Decode all DTCs P0305 - 35-10 - Please Register/Activate - Intermittent ROSS TECH DEFINITION: 16689/P0305/000773 - Cylinder 5 Misfire Detected 16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected it says something about camshaft position is this timing belt related? i got the belt changed professionally at 89k the car now has almost 97k. if it was timing belt related would it take 8k miles to detect it? i changed the spark plugs at 75k but the mechanic i got it changed from said the cheap plugs would be OK to use so he bought some cheap copper ngks single tips i believe. i havent been back to that mechanic after he changed the plugs and did not get my belts replaced by him. the car runs like normal no loss of power no check engine lights. i just scan my car every week to see. last month i had 16825/P0441/001089 - EVAP Emission Control Sys: Incorrect Flow but i cleaned the purge valve and lots of black crud came out and the code went away. i also had the code (last month) 16804/P0420/001056 - Catalyst System; Bank 1: Efficiency Below Threshold but i was low on oil so i thought since i park on a steep hill the oil went into the cats and blocked the holes. so i started parking it in my garage and after a long drive the code was gone (and used some stp fuel injector cleaner) AND i had the oil was only 2k old and i changed it my self and made sure it was full multiple times but it became low and i had to add about 700ML. the oil could not have been lost from leaks because i had my leaks fixed. i wrote my old fault codes so maybe someone can make a connection (if any?) ALSO since the code was intermittent is it OK to drive the car? i drive the car to work which is 5 miles away and 5 miles back. ill be using my 2.7 for long trips for now. ALSO noticed when i started the car from cold the rpms were bouncing around 100rpms for a couple of seconds and then normal. i read a thread that a guy fixed his P0300 by replacing the oxygen sensor. this doesnt seem like it would help to me what do yall think?

[2.7taudi]

update: from this morning i drove the car 40 miles and i just now scanned it again and no fault codes were found. does this mean the ecu just tripped a code?

so in cylinder 5 the misfire i had i can rule out the timing belt issue or it would have caused the whole bank to misfire i think. if the code comes back im thinking its probably a bad spark plug or the wire from the distributor cap to the plug (coil pack?) or maybe a dirty injector.

But what does the p0300 mean? does it mean all the cylinders are misfiring? if it does why would it just specify cylinder one and not the others?

i could use any help. car is at 97k and this is the 1st misfire.