Questions and Answers
Mustang Misfire
Q. Dear sir, I am having a problem with a 1995 Ford Mustang GT, 302 V-8, automatic, 90,000 miles, fuel injected, rack and pinion, with P/S, A/C, cruise and no ABS. the main problem started as a high rpm miss above 2000 rpm, especially if you are accelerating hard.
New plugs Accel 9mm wires, Accel distributor cap and rotor have been installed. I have also installed 5 different coils, the last one being a $50.00 Accel heavy-duty coil. I started replacing the coils because of blue sparks between the body of the coil and the metal frame surrounding it. When I replaced the first coil the car ran fine for five or six months.
With each coil replacement the high rpm miss returned along with the blue sparks (visible in the dark) at the coil in less time. The Accel coil went bad immediately. Something is causing the coil to go bad. I have checked connections and wires between the distributor, coil and ignition control module. I took the ECM in and had it tested, its okay. Some corrosion was found in the wires that were cleaned up.
The check engine light comes on periodically but does not stay on. I have retrieved the following codes from the computer, 117, 118, 217, 617, 618, and 917. The car seems to run okay below 2000 rpm's however it does not have the power it had before. Also you can see blue sparks (in the dark) around all 8 plugs I think the fire is coming from under the boot to the plug. The plug sparks were there before the miss and the car ran fine. I have seen these plug sparks on other vehicles and they seem to run fine.I did use dielectric grease when installing the plugs. Any suggestions you have would be greatly appreciated.
Thank you…
A. First off I would make sure you are using Motorcraft AWSF-32C spark plugs. It does make a difference.
The codes you are getting are:
DTC 117
Engine coolant temperature sensor circuit below minimum voltage 254 degrees F indicated.DTC 118
Engine coolant temperature sensor circuit above maximum voltage/ -40 degrees F indicated.DTC 217
Powertrain control module detected coil 3 primary circuit failure.DTC 617
1-2 shift error.DTC 618
2-3 shift error.I can't find any code 917.
The codes that are being displayed would make me believe there is a harness wiring problem. Almost unheard of in a Ford. Yeah, right. I would suggest this, get some fairly heavy wire and run a new ground from the engine to the body and then to the frame, such as it is, and clear all the codes. Drive the car with the new ground wires and that may cure the problem.
If it does you can either leave the new ground wires in or, if you're like me, dig into the wiring and find out where the problem is exactly. Also, lose the grease on the plugs and wires. They should be dry. Some spray silicone is okay to seal the spark plug wires and distributor cap and keep moisture out.
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