po300 Quick answer needed
It's probably neither the coils or the transmission, more than likely it's because of your cams and I'll explain why. There is a table in the rom image (more than likely the 94170015 update rom for your '03) that is a timing advance for EGR, in stock form up to 8-10 degrees of timing is added for lower load rpms and it's matched to the stock cam set. With an upgraded cam set you're now allowing more exhaust gas to recirculate in when the EGR valve opens, so the timing must be decreased so as not to cause the misfire that your ecu is picking up for your p0300 code.
Of course these days most people just disable the p0300 check completely in the ecu without timing adjustments to the EGR timing advance table, but if you don't want to go through the hassle of adding the blobbits to your rom, reducing the timing in that table works just as well. I should know, I've been running with the reduced timing for about 2 years now without a single p0300 since I found what the table does.
Of course these days most people just disable the p0300 check completely in the ecu without timing adjustments to the EGR timing advance table, but if you don't want to go through the hassle of adding the blobbits to your rom, reducing the timing in that table works just as well. I should know, I've been running with the reduced timing for about 2 years now without a single p0300 since I found what the table does.