Hello, This is only my first post so please be kind I've got a 2003 Mazda 6 2.3L that is currently suffering from a very rough idle -- it runs fine under acceleration. The only mod to the vehicle is a cold air intake that was installed 6+ years ago. I removed the filter for the CAI a couple of months ago to clean it, and then not long after that I got 2 DTCs: 2187 and 2177 (System Too Lean off Idle and System Too Lean at Idle). So, then I used my scanner and OBDWiz to clear the codes and log the performance. I then got P0300 and P0303, in addition to the original P2177 and P2187 codes. I know that some of the things to consider are the MAF sensor (which I have cleaned), the front O2 sensor, vacuum leaks, the PCV valve hose, etc. I have also heard that the CAI can be the culprit, but since this one has been working fine for several years, I don't think it's the problem. What I am wondering is if the information saved from my scanner will give me a clue so that I don't have to play trial and error with a bunch of expensive parts. I've attached the log file recorded while sitting at idle, the trouble code report, the freeze frame report, and the On-Board Monitoring report. If anyone can give me some advice I would certainly appreciate it!