Symptoms of intermittent coil pack failure? - MustangForums.com



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Old 10-27-2015, 11:01 AM
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Old 01-07-2012, 12:14 PM   #1
powellst
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Default Symptoms of intermittent coil pack failure?

I have an 02 convertible w/ 50k miles , and lately it's been having been having problems that it seems to chug and misfire going up hills or doing a constant speed with steady throttle pressure. It also seems very hesitant when accelerating, likes the engine is really holding back.

No SES light.

I cleaned the throttle body, MAF sensor, changed the fuel filter, new air filter, and will be changing out the plugs/wires next week. I also ran a bottle Seafoam through the fuel tank.

A friend at work is leaning toward a problem with the coil pack, but others say no way it could a coil pack problem without a code being thrown.

The only other other problem I've had is the SES light came on a couple of months ago right when I first got the car, and changed out the DPFE sensor (used an BWD brand from Advance instead of Motorcraft), cleared the code, and no further SES lights.
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Old 01-08-2012, 09:56 AM   #2
mustangmike09
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Coil pack is a common failure and as I just posted in another thread simular here.

I did not have a code.

Please start by checking your spark plugs if you have not yet. BWD usually isn't a bad brand, but Id try and stick with anything motorcraft. I am using a bwd coil though

But coil packs usualy have an under load problem instead of an constant problem. So definately check plugs.

I checked plugs, were fine. So I bought a new set of wires and coil. Wires didn't cure it but coil did so I took wires back and was only out the money I needed to spend.
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Old 01-09-2012, 02:39 AM   #3
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A bad coil pack won't always throw a code. But, as mustangmike09 mentioned, a coil pack problem doesn't normally reveal itself when running at a constant speed. It usually occurs when under load like when driving up a hill or accelerating to highway speed.

I would diagnose the problem & illuminate the other possibilities first. Like bad spark plugs, wires, fuel pressure etc etc. Fuel pressure can be verified/tested by renting a fuel pressure tester kit from your local auto parts store (you get your money back when you return the kit) and running a fuel pressure test. You want the pressure to build quickly when you put the key in the ON position (which starts the pump and primes the sytem). You also want it to be at the proper level (I don't know what that is off hand). When the car is idling, you want it to have steady pressure. Rev the motor to 2k RPM's and keep it constant. The fuel pressure should be higher but still steady. There are a bunch of video's on YouTube, and instructions on the interwebs on how to do all this. Good luck...
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Old 01-10-2012, 07:19 AM   #4
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Im having a similair problem with my 2002 v6 mustang i cant get it
to stop skipping or what i would call skipping. Its fine if the rpm is contant but as soon as you give it gas its wants to bog down and somewhat skip jerking the car back and forth. Ive replaced the whole injection system everything from the coil to the plugs. Ive checked the trans fuild and its at the correct level and it doesnt smell burt at all. The trans only has about 50k miles on it and runs smooth through every gear. Its only been doing this for about 2 weeks. Anyone have any futher ideas cuz im stumped.
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Old 01-10-2012, 07:20 AM   #5
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In addition to my last post i also havent had the SES light come on.
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Old 01-11-2012, 02:16 AM   #6
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vacuum leaks, fuel system
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Old 02-20-2012, 06:12 PM   #7
GreggBig
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My son and I both have V6 Vert Mustangs. He's is a 01 and mine is a 02. And both are having the same "misfire going up hills or doing a constant speed with steady throttle pressure. It also seems very hesitant when accelerating, likes the engine is really holding back". We have changed wires and plugs..... No improvement. Changed fuel filters.... No improvement.
So, it looks like we will replace the coil next. For only $70, seems like the correct next step.
However, the Ford dealership suggested the throttle body may be an issue, but based on this post, we will try the coil.
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Old 02-21-2012, 02:12 AM   #8
Daehawk
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Quote:
Im having a similair problem with my 2002 v6 mustang i cant get it
to stop skipping or what i would call skipping. Its fine if the rpm is contant but as soon as you give it gas its wants to bog down and somewhat skip jerking the car back and forth. Ive replaced the whole injection system everything from the coil to the plugs. Ive checked the trans fuild and its at the correct level and it doesnt smell burt at all. The trans only has about 50k miles on it and runs smooth through every gear. Its only been doing this for about 2 weeks. Anyone have any futher ideas cuz im stumped.

Air filter.
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Old 02-21-2012, 01:33 PM   #9
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i work on police vics everyday and have had them come in with a mis fire but no check engine light and found the problem to be a bad coil pack also i have seen a dirty MAF casue the car to act up ( like a mis fire) with no light.
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Old 02-23-2012, 01:25 AM   #10
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just thought id add that im having a similar problem with a misfire and what seems like skipping while accelerating. i got new air filter, plugs, and wires. let me know if the coil pack works for you guys.
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