2004 Z MT with about 104K miles. I randomly get a P0300 but only when the car has sat for a few days with out starting it. It'll start up with a rough idle and then the idle is fine after a minute or so. I have a UltraGauge which reads many things like engine temp, volts, MPG etc and also reads engine codes (mainly the reason i have on the car). I daily drive this car and I never get the code when im driving it daily. I clear the code and does not come back on. Car runs fine with no issues. As for mods car has Greddy catback, JWT pop charger everything else is stock. I dont drive the car hard. Only other time it gave me a code was when one of the ignition coil went out. I replaced it with a new one and code was gone but that was a while back. What do you guys think?

 

You likely have another coilpack going South.

Exact same experience. I got lucky, when the DTC showed up it showed the exact cylinder, eg, P0304 instead of “random P0300”. Replaced ‘em all anyways. Cheap. OE units for about $125.

 

thanks thats what i was thinking but since it hasnt given me an exact cylinder number im not sure if that will be the issue. Im hoping i will since its an easy fix and not expensive. I did think of just replacing all of them all together.