Hey all, new member and first time posting.
I got a odd issue, I have a 2016 Mazda 3 iSport 2.0L hatchback stock. At 132,000 miles I got my oil changed as well as plugs and belts replaced. They ran a 2 part Valvoline cleaner as well. Drove home fine but next day took 5 attempts to start. It was misfires I think.
Once it started and idle was good I headed down the road. Got up to 45 mph and then pushed the pedal to the metal to go around and Sunday driver.
Once my RPMs redlined it started chugging and misfire code p0300 and p0303 popped up.
Thinking maybe bad plug or wrong gap I took it back to the shop. They tested their work, swapped coil pack and plug, checked gap and ran diagnostics. Said their work was sound and tried to tell me the cat was the issue. I know that was bull shit.
I discovered the hydraulic belt tensioner was leaking and though "oh,there's my problem. They busted the boot or the seals in the tensioner" replaced it and the bet definitely got tighter but the issue didn't go away.
If I baby it while I drive and or drive it like a normal person lol there's 0 issues. The moment I push the accelerator to the floor and click the button causing my RPMs to go up it will misfire.
The shop put NKG iridium plugs in it but to be on the safe side I picked up some $11 iridium plugs from O'Reilly's and put in it myself but the issue still remained. I have also ran a can of CRC intake valve cleaner through the car but there's still no change.
Local garage (not the same one) told me based on the symptoms he thinks that cylinder 3 has a lot of carbon built up on it. Now it was at this point in my life and my 6 years of owning this car that I learned what a direct inject engine was and spent the last few days doing massive amounts of research on them.
It could just be coincidental that all of this happened the day after I took it to a shop and had them change the belts and plugs but I'm at my wit's end and can't seem to figure this thing out.
Really cannot afford another shop bill at this point so I've been trying to figure it out myself if anyone has had any experience with a similar issue or with this issue any advice would be very much appreciated. Here is a freeze frame of my Innova 5210 but I have no idea how to read these lol. Oh and I should add that I drove it to about 1/4 tank, dumped a bottle of cataclean in and drove to about 25 miles to E. Filled at at shell with Top tier sticker to fill it up with V-power gas and added a bottle of Red Line to hopefully clear injectors if one is partially clogged.
![Image]()
I got a odd issue, I have a 2016 Mazda 3 iSport 2.0L hatchback stock. At 132,000 miles I got my oil changed as well as plugs and belts replaced. They ran a 2 part Valvoline cleaner as well. Drove home fine but next day took 5 attempts to start. It was misfires I think.
Once it started and idle was good I headed down the road. Got up to 45 mph and then pushed the pedal to the metal to go around and Sunday driver.
Once my RPMs redlined it started chugging and misfire code p0300 and p0303 popped up.
Thinking maybe bad plug or wrong gap I took it back to the shop. They tested their work, swapped coil pack and plug, checked gap and ran diagnostics. Said their work was sound and tried to tell me the cat was the issue. I know that was bull shit.
I discovered the hydraulic belt tensioner was leaking and though "oh,there's my problem. They busted the boot or the seals in the tensioner" replaced it and the bet definitely got tighter but the issue didn't go away.
If I baby it while I drive and or drive it like a normal person lol there's 0 issues. The moment I push the accelerator to the floor and click the button causing my RPMs to go up it will misfire.
The shop put NKG iridium plugs in it but to be on the safe side I picked up some $11 iridium plugs from O'Reilly's and put in it myself but the issue still remained. I have also ran a can of CRC intake valve cleaner through the car but there's still no change.
Local garage (not the same one) told me based on the symptoms he thinks that cylinder 3 has a lot of carbon built up on it. Now it was at this point in my life and my 6 years of owning this car that I learned what a direct inject engine was and spent the last few days doing massive amounts of research on them.
It could just be coincidental that all of this happened the day after I took it to a shop and had them change the belts and plugs but I'm at my wit's end and can't seem to figure this thing out.
Really cannot afford another shop bill at this point so I've been trying to figure it out myself if anyone has had any experience with a similar issue or with this issue any advice would be very much appreciated. Here is a freeze frame of my Innova 5210 but I have no idea how to read these lol. Oh and I should add that I drove it to about 1/4 tank, dumped a bottle of cataclean in and drove to about 25 miles to E. Filled at at shell with Top tier sticker to fill it up with V-power gas and added a bottle of Red Line to hopefully clear injectors if one is partially clogged.
