Mazda CX-3 Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
I have a misfire P0304 cel, cylinder #4. on my 2016 cx-3 with 110,000 miles. I have already swapped coils and replaced plugs with factory ngk plugs. car drives ok but seems to stumble below 2k rpm. I can see hundreds of misfires in a few minutes on my scan tool on cyl 4. I clear the cel and it comes right back. Im thinking I have a bad injector. I just ordered one injector from dealer. any one have any info on removing fuel rail, how to release pressure, also I just want to remove one injector not all 4 as the teflon seals get damaged and you need a special tool to put a new one on. Any help would be great, thanks
 

·
Registered
2019 CX 3 Touring
Joined
·
29 Posts
I have a misfire P0304 cel, cylinder #4. on my 2016 cx-3 with 110,000 miles. I have already swapped coils and replaced plugs with factory ngk plugs. car drives ok but seems to stumble below 2k rpm. I can see hundreds of misfires in a few minutes on my scan tool on cyl 4. I clear the cel and it comes right back. Im thinking I have a bad injector. I just ordered one injector from dealer. any one have any info on removing fuel rail, how to release pressure, also I just want to remove one injector not all 4 as the teflon seals get damaged and you need a special tool to put a new one on. Any help would be great, thanks
Try using Lucas fuel additive before you change anything
Liquid Font Ingredient Logo Transparency
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #3 ·
I did add that to the fuel tank and it didnt do much, I also thought that it is a direct injection engine so the intake valves might be carboned up so I ran a can of CRC intake valve cleaner though the intake while engine was a 2000 rpm. I still have misfire on cyl 4 and p0304 code, I also checked compression and all 4 cyls were good at 120 psi.
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #4 ·
Update. I pulled the intake off, and #4 cyl intake valves were caked with carbon buildup, the can of crc cleaner I ran thru it didnt do much I quess. Just #4 cyl were bad the other 3 were fine, because #4 is closer to the pcv hose in the intake. I cleaned the two intake valves up with a toothbrush and plastic stick and vacumed it all out. I also pulled the Fuel rail and replaced #4 injector with a new mazda oem one. The tip of the old injector was completely clogged with carbon. Car runs like new now, no Misfires on the scan tool anymore and I have all my power back. I just hit 100k miles and i drive the car very aggressive lots of full throttle so there is a problem with pcv system in the cx-3, It should have a removable catch can that you empty with every oil change.
 

·
Registered
2019 CX 3 Touring
Joined
·
29 Posts
Update. I pulled the intake off, and #4 cyl intake valves were caked with carbon buildup, the can of crc cleaner I ran thru it didnt do much I quess. Just #4 cyl were bad the other 3 were fine, because #4 is closer to the pcv hose in the intake. I cleaned the two intake valves up with a toothbrush and plastic stick and vacumed it all out. I also pulled the Fuel rail and replaced #4 injector with a new mazda oem one. The tip of the old injector was completely clogged with carbon. Car runs like new now, no Misfires on the scan tool anymore and I have all my power back. I just hit 100k miles and i drive the car very aggressive lots of full throttle so there is a problem with pcv system in the cx-3, It should have a removable catch can that you empty with every oil change.
I'm glad you found the problem, have you ever replaced the pcv valve? Also I always run a bottle of Techron or Lucas fuel additive when I go on a 2.5 hour trip on the expressway every six months or so, my car still has low miles, 25K, my previous car a 2009 Honda Fit, bought it new, sold it with 160K always used the same when I traveled, never had an issue.
 
1 - 5 of 5 Posts
Top