P0304 Error. Help tried everything!

[danielkote]

Hi guys

I have 2016 cx5 with p0304. It goes to limp mode with ac on and under load.

Me and my mechanic replaced injector-resistance tested, coil, plug, checked wiring, did walnut blasting valves, checked compression, even swapped ECU..still same problem. Getting desperate. Does anyone have any ideas? Thank you

 

[N7turbo]

Does it go into limp mode under load with AC off?

 

[danielkote]

Does it go into limp mode under load with AC off?

So far it has not, I guess max AC fan adds too much load, but it does have slight jerk even idling. Can feel misfire

 

[N7turbo]

Is there anything else about the electronics that has been modified?

I wonder if it's your alternator? Have you measured the voltage of the battery while running?

 

[danielkote]

Is there anything else about the electronics that has been modified?

I wonder if it's your alternator? Have you measured the voltage of the battery while running?

Nothing was modified. I will ask my mechanic about voltage

 

[cz5gt]

Mazda oem plugs and oem coil or aftermarket?

 

[danielkote]

Mazda oem plugs and oem coil or aftermarket?

Aftermarket, getting 1 ngk laser plug for cylinder 4 today to see. Do you think one in misfire cylinder will show difference? If thats it of course will buy a set. Also thinking rocker arm

 

[N7turbo]

We've seen a lot of issues with aftermarket coil packs on the forum here.

 

[elementCX5]

We've seen a lot of issues with aftermarket coil packs on the forum here.

Not a mechanic, but I watch YouTube mechanics such as South Main Auto, Royalty Auto Service, and Rainman Ray.
The amount of times aftermarket parts or knockoff Ebay/Amazon parts cause issues is way too high.
If its something necessary for smooth operation and drivability, stick with OEM from a reputable vendor.

 

[danielkote]

Not a mechanic, but I watch YouTube mechanics such as South Main Auto, Royalty Auto Service, and Rainman Ray.
The amount of times aftermarket parts or knockoff Ebay/Amazon parts cause issues is way too high.
If its something necessary for smooth operation and drivability, stick with OEM from a reputable vendor.

Just swapped oem plugs, same thing

 

[CC58]

You need to isolate the misfire to determine which cylinder is not firing and why. Below video shows how to do that. My guess is a bad injector coil. Pretty common. If so, Mazda sells them for not much more than Autozone and way more reliable.

 

[N7turbo]

My guess is a bad injector coil. Pretty common.

Did you mean ignition coil? If so, we almost never see these fail on the boards here. Not saying it doesn't happen, but it doesn't seem to be common.

 

[felixd]

Have you swap one of the coil pack to cyl 4 and check if the other cylinder has the same problem ? then you can assume that the ignition coil pack is the problem.

Also check if any intake vacuum hose are worn out / have cracks on them & check PCV Hoses under the intake manifold.

Hi guys

I have 2016 cx5 with p0304. It goes to limp mode with ac on and under load.

Me and my mechanic replaced injector-resistance tested, coil, plug, checked wiring, did walnut blasting valves, checked compression, even swapped ECU..still same problem. Getting desperate. Does anyone have any ideas? Thank you