I would really appreciate any suggestions that might help resolve my issue. About a week ago I got a flashing check engine light. When I pulled the codes I got P0303 and p0304 as well as pending P1399. I took my car to Ballade Sports back in January when I was having a misfire issue. They did a compression and leak down test and determined one of my injectors was/had failed. At that time I replaced all 4 injectors as well as 4 new spark plugs. They also did a Valve adjustment while they had it there. Now that I got the misfire codes I figured it must be coil packs so I went ahead and replaced all 4 yesterday. This did not resolve my problem. The codes I have now are P0304 and P0300. I also noted that my fuel trim was fluctuating between -15 and -21 (units?) Any suggestions on what i can do? Only modification on my car is K&N intake

TL;DR Have misfires and running rich. already had valve adjustment and replaced coils, spark plugs and injectors. What next?

 

Also when coming to a stop my idle rpms will usually dip really low and recently it has just been stalling out as soon as I put it in Neutral and the revs drop