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Having engine misfire problems?

Tiny
RAL2CP377
  • MEMBER
  • 2004 MERCURY SABLE
  • 3.0L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 105,000 MILES
Hi --
I have a 2004 Mercury Sable with the V6 3.0L DOC Duratec engine. I've been having misfire problems off and on ever since I purchased it, used, in 2011. The misfires are most apparent when the engine is under load (going up a hill) or I'm trying to accelerate.

I've switched out ignition coils from time to time in the past, which often clears up the problem temporarily, but it seems to always eventually return. It does seem to be much worse in rainy weather, by the way.

I'd like to know what the resistance specs are for the primary and secondary circuits on the coils, so I can check that out on the ones I have installed, as well as on a couple cheapies (15) I ordered from Amazon. Also, I have no idea what the range of "good" readings is for those specs, if you happen to have that information.

Thanks so much for any assistance you can offer on this!

Robert.
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Wednesday, August 24th, 2016 AT 12:11 PM

35 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
This happens when the plug wires break down I would do tune up with spark plugs and wires using all motorcraft parts here are two guides to help us fix the problem.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

and

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

Please run down these guides and report back.
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Wednesday, August 24th, 2016 AT 4:03 PM
Tiny
RAL2CP377
  • MEMBER
  • 3 POSTS
Thanks for you time in replying -- much appreciated.
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Friday, August 26th, 2016 AT 3:19 PM
Tiny
RENEE L
  • ADMIN
  • 1,260 POSTS
Please let us know how it turns out so it will help others
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Tuesday, August 30th, 2016 AT 10:40 AM
Tiny
RAL2CP377
  • MEMBER
  • 3 POSTS
My OBDII reader was saying I had two bad ignition coils, also giving a P0354 "Primary/secondary coil failure" message. I was going to replace the two indicated bad coils, instead bought a set of six at Amazon for $38.50 (yes, that's right, a complete set of SIX ignition coils for $38.50!). Of course I was initially skeptical, but.... 176 reviews of the coils, 150 of the reviews gave them 5 stars. I know most "experts" would say don't do it, but it's difficult to ignore those numbers. They're sold by "ENA" -- a company I've never heard of. https://www.amazon.com/gp/product/B002PGRJN8/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I installed three new coils (the three that are easy to access without removing the intake manifold, and so far the car is running absolutely fantastically well. I'll try to remember to give an update here in six months, a year (etc??) to report on how they hold up as time goes on. I got all new parts including the coil the engine has never run better thanks again! I love this site I cant believe it is free.

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Wednesday, August 31st, 2016 AT 10:58 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
That sounds great! Nice work on the fix, please let us know if they last thanks for using 2CarPros we are here to help

Best, Ken
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Thursday, September 1st, 2016 AT 7:59 AM
Tiny
MICHAELDOCONNOR86
  • MEMBER
  • 1 POST
  • 2004 MERCURY SABLE
  • 3.0L
  • V6
  • AUTOMATIC
  • 102,000 MILES
I bought this car about a year ago. Everything was smooth for about six months no check engine light or any other problems. Until recently I would start the car and the engine would jerk for a while then stop when I am driving. If I stop at a stop sign it jerks and the check engine light periodically comes on from time to time but never stays lit. I had a complete tune up since this started and it seemed to have fixed the issue for a little while but the problem came right back. The last time the light came on I got the codes read P0306, P0316 and P0325. Can anyone help me solve this problem I would greatly appreciate it?
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
JIS001
  • MECHANIC
  • 3,411 POSTS
P0325 is most likely been set because of the vibrations from the engine when it misfires. The misfire code should be addressed first. P0316 would indicate that the misfire is happening at start up especially if vehicle sits for a while.

Have the #6 spark plug removed and let vehicle sit overnight. Pressurize the cooling system and let it sit over night also if possible lift up the fuel rail on bank2 with the injectors still attached. Cycle key on and off a few times without starting to pressurize the fuel line and place some paper under the injectors.

In the morning check paper for signs of leaking fuel injectors. If the paper is dry then fuel injectors are ok. Using a bore scope look inside and examine the piston for coolant. If it is wet then the cylinder head will need to come off to properly pressure test head and examine the block for any damage.
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
DAVEMALLARY
  • MEMBER
  • 14 POSTS
  • 2002 MERCURY SABLE
  • 3.0L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 65,000 MILES
My car has I PO301 and a PO325. The misfire is random. I am looking for testing procedures. I am going to swap injectors to see if I can move the problem, but I am not sure how to test the coil. Does this car have a waste spark system so I can swap wire locations.(It does not have COP'S)

I am also trying to find the test procedure for the knock sensor. I have checked for resistance. There was no reading. Open circuit.
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
DAVEMALLARY
  • MEMBER
  • 14 POSTS
Swapping the injectors made no difference.
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
So you checked resistance across the sensor itself? If you have an open circuit here then I would replace the sensor and retest the misfire because a faulty knock sensor can cause an intermittent misfire.

I attached the testing for this knock sensor code as well however, I suspect you won't get past step 4. They have you testing the circuit from the PCM but if you checked the sensor and it is open then I suspect that is the reason for this code.

Let me know if you have questions. Thanks
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
DAVEMALLARY
  • MEMBER
  • 14 POSTS
Yes, I checked resistance across the sensor itself, and it is open. I can't find the Knock sensor pid on my scanner. I have an Autel 708. I don't really know how to use it, I bought it for educational purposes. I will get a new knock sensor and go from there.

I suspect the coil is weak. I was using my spark tester to see how far the spark would jump from the coil. #1 would not jump out of the top of the coil, but # 4 would jump out about three quarters of an inch. I did not test the others. Does that sound like a weak coil to you?
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Yes. It does sound weak. Especially when compared to another. I would replace that as well while you are in there. Keep us updated with what you find. Thanks
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
DAVEMALLARY
  • MEMBER
  • 14 POSTS
I meant to update this sooner. I replaced the coil and the PCV valve. I ordered the wrong knock sensor so it did not get replaced. The codes are still gone and have not come back. The car has developed an intermittent oil leak. It will leave a puddle and a trail of oil occasionally after starting the car. It has happened 3 times that I know of. Do you have any guesses on what it could be?
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
No problem. Thanks for updating us. That is good to hear.

As for the oil leak we need to get a new post started as we have to keep each thread to one topic so that others can find the solutions to the different issues. They won't find an oil leak solution under this topic.

https://www.2carpros.com/questions/new

Let's start the new post after you clean the oil off and start looking daily for where it is starting to drip from. That info and any pictures will help us figure this out quickly. Thanks
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
CARMANMT
  • MEMBER
  • 19 POSTS
  • 2002 MERCURY SABLE
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 82,500 MILES
Hi, I have an -02 Sable with 3.0 DOHC engine and it has a low idle misfire. I found the PCV valvue was sticking and the L rubber boot that connects it to the air intake was sucked in so those I fixed but the proble persists. I ran the codes and it has the following P0113, P0301, P0316 and P0102.

The car accelerates without a problem and runs good at high speed, just at idle it has miss that comes and goes, sometimes the engige feels like a stall.

Any help would be appreciated.

Thanks
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
MATHIASO
  • MECHANIC
  • 1,209 POSTS
Hello!Carmanmt

P0301 says that the cylinder #1 is misfiring.
What need to be check is first of all the condition of the spark plug in that cylinder. Just describe me how it look like when you remove it.
Make sure any clamp athe manifold is tight enough and not loose.
Make sure the injector on that cylinder is not dirty, have the injectors clean at walmart.
Make sure the spark plug boot on #1 cylinder is not broken inside.

P0113, this code is about the intake air temperature,
the connector may be bad or the sensor is bad. It is located just after the air filter and it is squeezed in the big rubber boot from the air filter to the intake.

P0102
the MAF may be faulty or Check for loose tube clamps near the MAF sensor

P0316 this last code is a combination of all the code above.
Ask if you have questions.
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
CARMANMT
  • MEMBER
  • 19 POSTS
Mathiaso,

thanks for the reply. I will run those down and get back to you.
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
CARMANMT
  • MEMBER
  • 19 POSTS
Ok, I pulled plugs 1, 2 and 3 and they didn't look real bad, just a little build cleaned and put them back, checked for vacun leaks in hoses and manifold. Checked all the wires with ohm meter and for arching and they were fine, not that old. The removed the coild pack and found multiple cracks in the sides and bottom insulator, replaced that and it seems to be running fine now. Not sure if that was the only problem, no check engine light or eratic idle probles for now.

One question, do you guys know where the air intake tempature sensor is located or looks like on this engine, its not in the air intake boot, only thing in that arera is the MAF sensor.
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
MATHIASO
  • MECHANIC
  • 1,209 POSTS
Congratulation! You 're hire.
I'm happy the car is still running fine.
Look, the intake air temperature is located around the intake manifold I do not have picture of it for that particular model, I may ask some of my collegue if you still do not find it.
This sensor helps the PCM to determine spark timing and air/fuel ratio. Information from this sensor is added to the pressure sensor information to calculate the air mass being sent to the cylinders. The IAT is a two wire sensor. A 5-volt reference signal is sent to the sensor and the signal return is based upon the change in the measured resistance due to temperature.
Sending the chart in your email
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)
Tiny
CARMANMT
  • MEMBER
  • 19 POSTS
Sounds good, when do I start.

Now that you said its two wires, think I found it. Funny looking thing on the far side top of the intake air assembly, has a big black knob on it. Will try and take a picture and post it to share with others.

Thanks. With cars today, sure we will be talking agin.
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Thursday, October 22nd, 2020 AT 11:26 AM (Merged)

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