CX7 2007 Cylinder 3 Misfire Headache - Mazda Forum
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post #1 of 1 (permalink) Old 10-04-2018, 03:34 AM Thread Starter
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CX7 2007 Cylinder 3 Misfire Headache

Hi there

I am hoping someone can provide much needed advice on my 2007 cx7.

I had to replace my engine as after an oil leak it caused low compression in Cylinder 3. After 2 assessments it was agreed that a replacement second hand engine would be best way forward.

After replacing the engine the engine light keeps coming on and the diagnostic tool states that cylinder 3 misfire. ERROR CODE P303:FF. mechanic changed / swapped the coils around, cleared the light and i took it away. A few days later the light came on and it was running doggy.

The mechanic is now saying it is is the ECU or wiring harness.

I am trying to sell the car which is worth $8500 and I have already spent 4500 on it.

I don't know what to try or suggest. The mechanic is suggesting we replace the ECU and hope that it fixes it if not replace the wiring harness. (the sounds of things he isn't sure which one to look at and replace first)

There must be a way to test if its the ECU or wiring harness?

Thanks in advance for any help or suggestions.

Last edited by Rik Sta; 10-04-2018 at 09:10 AM.
Rik Sta is offline  
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