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Kevin, Auto Mechanic
Category: Mazda
Satisfied Customers: 2088
Experience:  Diagnostic technician
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I have P0301 popping up. I replaced all 4 spark plugs but

Customer Question

I have P0301 popping up. I replaced all 4 spark plugs but they looked good to me and my mechanic . I've got 2011 Mazda CX-7 120K miles
JA: Where exactly do you think the noise is coming from? And how long has this been going on?
Customer: i don't have noise - it is just the sign showing up on my dash board - started about 3 weeks ago
JA: Are you fixing your CX-7 yourself? What have you tried so far?
Customer: i have mechanic replace all 4 spark plugs (my CX-7 is 2WD)
JA: Anything else you want the mechanic to know before I connect you?
Customer: it will be hard to say something definitive w/o looking
Submitted: 11 months ago.
Category: Mazda
Expert:  Ron Z. replied 11 months ago.

Hi! Welcome to JustAnswer. Thanks for coming! I'm Ron Z and I'll be working with you on your question today.

Is this the 2.3L or the 2.5L engine?

Customer: replied 11 months ago.
2.3L - I guess
Expert:  Ron Z. replied 11 months ago.

Does this vehicle have Turbo?

Customer: replied 11 months ago.
Do you have any particular suggestions? I am not able to talk at this time
Customer: replied 11 months ago.
No turbo - just basic 2.3L engine - this is basic model 2WD
Expert:  Kevin replied 11 months ago.

Hi I'm Kevin my first recommendation would be to swap ignition cool from cylinder 1 with cylinder 2 to see if code changes . This will rule out the ignition coil on cylinder 1 which is fairly common for the coils to go down

Customer: replied 11 months ago.
I Forgot to mention - the mechanic swapped the 1st and 4th coils. The code stile shows P0301 - the first cylinder misfire
Expert:  Kevin replied 11 months ago.

Has a compression test been carried out ?

Customer: replied 11 months ago.
No - nothing but spark replacement and flipping coils between 1st and 4th cylinder. What strange is the light came on after about 2 miles of driving, I cleared it with my tool and it came back again - in about 5-6 miles. I cleared it again 2-3 times after and it always was coming back after several miles of driving with no light. Now, the last time I cleared it on Friday and as of Sunday - it does not come back at all! I drove about 100 miles already (including round trip from Riverside to Laguna Beach) and it is still clear. Is it possible that the new spark plugs kinda work themselves out to fit so "service light" is coming up?
Expert:  Kevin replied 11 months ago.

It's unlikely it may have been bad fuel that has worked its way through system is keep trying and see how u get on