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CTFordTech, Ford Technician
Category: Ford
Satisfied Customers: 4976
Experience:  Ford Master School Certified, Kia Elite School Certified, ASE Certified, A/C 609 Certified
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Ford Mustang my 2003 mustang started running rough all of

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my 2003 mustang started running rough all of a sudden (like overnite)then the" service engine soon" light came on.i got home and checked all the plug wires (80,000 miles -original wires!!)one of them was burnt and cracked ...i thought ..this is it ! ..wrong ...still running i changed all the plugs...still running rough pep like the night before ...i think the coil is going bad . these coils cant be diagnosed at auto zone and i dont know how to check one i guess i will have to buy a new coil for $ 80 ...what do u guys think ??any help will be greatly appreciated!! thanks in advance !! william buttke

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The coils are difficult to diagnois because they really cannot be tested unless they are not woorking at all or tested with special equitment to check the spark voltage outpupt. I have personally seen a lot of coils go bad so I believe that may be your problem. If you have a cylinder misfire code, you can first try swapping fuel injectors too see if the misfire changes cylindters to at least rule out that.

Customer: replied 6 years ago.
i dont have an obd scanner to check codes ..but on the yellow mustang web site ,most of the guys there said they would run a scan 4 or 5 times and not get any "missfire "codes...when they clearly could hear and feel the missfire...mine feels like when u would set timing on a reg distributor and be way off..the motor would almost shudder ...thats what mine does ,,,i am pretty confident it is the coil pack going bad if thats your opinion also ..i will be satisfied with that answer ....thanks again....will
I have seen more coils go bad than anything. Sometimes there is even a crack found on the coil and moisture can work it way in a cause the problem. Just something you could look for.
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Customer: replied 6 years ago.
hey, i replaced the coil is the type that is all in one sealed unit ..not individual coil packs.i am still getting the error code po352...could the spark plug wire shorting out on the block fry the ECM ? ,,,another mustang related web site said i may have fried the COIL DRIVER CIRCUIT in the ecm . what do you think ? is that possible/plausible??