I have 3 CEL codes related to misfire. It is misfire on cylinder 3, misfire on cylinder 4, and multiple misfire. I also have a "too rich" CEL and a "Idle Air" CEL on. I'm pretty sure I need to replace the IACV and my timing is advanced so I think that has to do with the running rich, but the honda guys said that timing has little to do with a misfire code. They think it would be more of a crank sensor or something. How do I troubleshoot this ?