Aussie MPS issues

[Stephen Johns]

Hi guys,
Onto my 2nd Mazda 3 MPS now.
Just rebuilt engine on this due to failed ring (caused by detonating) and now back together, having issues with it running properly.
Getting multiple random misfires (p0300) and has no power.
New Plugs gapped to 0.70mm and 2 are lean, 2 are rich.
New coil packs installed and also swapped back to old ones just in case with no change. car actually ran and idled prior even though only 65psi on bad cylinder so must be electrical l am thinking.
About to start checking wiring and sensors.

 

[Raider]

Had to translate the gap, it's correct.

Injectors. Cleaned? What seals are in there? Oem coil packs and not the yellow aftermarket ones? How is the electrical harness?

 

[Cfoldone]

While not absolutely sure, but my random 30x codes were partially because of cam position sensor. I thought was coils, but swapped with my perfect running other speed. Coils were not the problem. So tried cam sensor, that stopped random cylinders misfire. Your richness has to be contributing since fuel mixture is very rich hard to get good ignition. Reading manuals it appears that ecu after it sends a coil fire command it watches cam sensor and crank pulse wheel and if a slow or fast position is calculated different than physical sensors --immediately after fire command-- will cause the random 30x codes. At least that's what I get with my reasoning...I could be all wrong though, so hope it helps.