Hey guys! So my car is throwing this code and was wondering if you guys can help me out. The car has LOUD random backfires at idle and when I went around the block as well.

Tomei headers
Z1 testpipes
Z1 filter
Lower intake runners cast cleaning

I did install CSF aluminium radiator and Mishimoto slim fans but I doubt that has anything to do with this.

The mistake I did was having the injectors out in the open when I was cast cleaning the lower runners. I did notice small metal shavings on the tip when I was about to install them. Cleaned them out as much I can but I'm assuming shavings went inside and causing a leak when the spark plug isn't igniting. I pulled all the plugs and they were all wet.

I do have HR injectors sitting in my garage. I searched around and found out that the DE and HR injectors are pretty close. Will I will need a tune if I install the HR injectors?

at 3 bar (43.5 psi)
DE injector flows 306cc/min
HR injector flows 309.25cc/min

Found the flow test here.
https://maxima.org/forums/all-motor/...omparison.html

 

Not sure if fuel since Septembre 2017 is considered old. That was the last I fuelled up.