96 jetta P0304 code

Has anyone had a similar problem and what did you do to fix it? My 96 jetta gls has a p0304 and p0300 codes for the number 4 cylinder. I had to replace the coil and mas airflow a couple of days ago and I have reset the computer (several times), now when I drive it more than 2 blocks the engine light comes on and these 2 codes are pulled out. I have replaced the spark plugs, checked the cap and rotor and did replace the plug wires about 15,000 miles ago. Anyone have any suggestions?

How are you errasing codes, I disconnected the battery also and the codes come back. Use a proper automotive scanner to clear codes and my codes did,nt come back. You did,nt say how vehicle runs after the work you performed. If ok even after codes come back, just clear codes properly.