Mazda 6 Forums banner

P0302 - Mazda Cylinder 2 Misfire detected

11K views 8 replies 4 participants last post by  waughoo  
#1 ·
Hello,

I need help with my 2004 Mazda 6 3.0L. Getting bad acceleration around 45mph and horrible gas mileage.

Had P1410 Vad, fixed that. Then got P0171 and P0300. Cleared those via centech handheld. Restarted car and now
get P0302....

Not sure where to check and really afraid of local mechanics and dealerships and they claim it could be anything and want me to bring in and pay them thousands...not gonna happen.

I changed these so far:
- Spark Plugs (6)
- EGR Valve
- EGR Solenoid Valve
- Purge Valve

Also, previous owner installed a CAI air filter. What a mess.

Any help appreciated.
 
#2 ·
I have the same vehicle. The problem very frequently lies with the Coils. This vehicle uses coil on plug (COP) ignition.
I recommend Denso 6736005 (OEM) and replace all 6. Likewise, you must be running at least platinum (or better) plugs
I am using Motorcraft (OEM)

I have included links above.

Take the CMP sensors out and wipe off the metal shavings. Do the same with the CKP down below. Each uses a single 8mm or 10mm socket. Super easy and it really smoothed out my engine beyond correcting the misfire from the coils.

And pray to whatever god you subscribe to that it didn't destroy the warm-up catalysts.
 
#3 ·
hello,

i need help with my 2004 mazda 6 3.0l. Getting bad acceleration around 45mph and horrible gas mileage.

Had p1410 vad, fixed that. Then got p0171 and p0300. Cleared those via centech handheld. Restarted car and now
get p0302....

Not sure where to check and really afraid of local mechanics and dealerships and they claim it could be anything and want me to bring in and pay them thousands...not gonna happen.

I changed these so far:
- spark plugs (6)
- egr valve
- egr solenoid valve
- purge valve

also, previous owner installed a cai air filter. What a mess.

Any help appreciated.
when my 2003 mazda 6 had a cylinder 1 misfire i changed all 6 spark plugs and cylinder 1 coil pack. Solved the issue for me
 
#5 ·
The connector is attached to the sensor. The sensor is held in place by one bolt. un-clip the connector and unscrew the bolt to slide the magnetic sensor out. Wipe the fine metal powder that accumulates on the magnet, make sure the o-ring is intact and slide it back in and reconnect. that's it.
Two camshaft sensors (CMP) are at the front of each cylinder head and the crank sensor (CKP) is down on the back side of the front of the engine (take off the passenger wheel, behind the splash shield, and look to the back of the crank pulley)

Since you have cylinder specific and general misfire codes I would spend the $150 and do them all. The catalysts will cost $1500 if you have to do them (4 cats and 4 O2 sensors)
Image


This was my converter. My misfire was mild enough to not trigger any codes at all. If let run long enough this happens. Even worse is when a tiny particle is ingested through the EGR and destroys a cylinder and the motor dies.
No bueno