How to fix below error codes: P0150,P1931,P0304,P0300 for this car? Model:A4; Maker:Audi; Year:2001

SOURCE: 2004 Audi A4 3L won't start

P0130 is 02 sensor bank 1 and P0150 is 02 sensor bank 2.

SOURCE: I am workiing on a 1999 toyota carolla has a misfire

Here is a good site for OBD II trouble codes.  P0300: Random/Multiple Cylinder Misfires Detected, P0301: Cylinder 1 Misfire Detected, P0304: Cylinder 4 Misfire Detected.

SOURCE: 2001 audi a4 1.8 random misfire

Have you changed the coils at each misfing cylinder? I had a misfire on cylinder 3, running really rough with flashing check engine light when engine was warm. The Check Engine light did come on solid after the misfire cleared. Swapped the coil with another cylinder and the misfire code followed the coil, so I replaced the suspect coil with a known good one. Voila, problem solved. My vehicle is a 2001 Jetta 1.8t, and from what I've read on the internet, failing coils is a very common problem. Good luck.

SOURCE: 2005 Audi A4 1.8T QT, cylinder 4 misfire p0304

I too have the same problem on my 2005 1.8t B6. I noticed a hole in the breather hose coming off the valve cover that runs to another port under the intake manifold. I have the hoses on order and should be here on Wednesday. I'll post again if that fixes my problem.

SOURCE: P0302,P0303,P0304;P0300 and P1399 found by the

From www.hondasuv.com:

The P1399 random misfire along with one or more of these codes: P0301, P0302, P0303, P0304 -- indicates a problem with the valves. The B20 engines in the 1997-2001 CR-Vs are known to have problems with valves tightening and then 'burning'.

So the first question is when was the last time you adjusted the valves? If you don't know or never have, then have them adjusted. Soon...