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Discussion Starter · #1 ·
My 2004 Duratec with 133,000 miles runs perfectly 98% of the time. About a month ago I was driving on the interstate with no problems. I get off at my exit, stopped at a traffic light and the car felt like it was going to stall (it didn't). When the light turned green I took off & it was smooth as silk. The Service Engine light came on.

The Wife and I went to a party, came out about 3 hours later for our 20 mile drive home. The Service Engine light remained on but the car once again ran perfectly.

The next morning I hooked up my Code Scanner. It had 6 codes, PO-351 thru PO-356 which are supposedly Coil related. The car has 1 coil per Spark Plug.

I knew this was out of my league so I took it to a local mechanic who I trust. I didn't tell him I had my own Scanner. He came up with the same 6 Codes & said what I thought "all 6 coils couldn't go bad at once". After further checking he said the Intake Manifold gaskets must be bad & the engine is "sucking air". He said under different temperatures the engine could act differently.

After $300.00 and a month or so later the engine felt like it was going to stall again. Occasionally while accelerating the engine "misses a beat". Most of the time it runs perfectly. Today the Service Engine light came on again. I hooked up the scanner, this time 4 Codes came up. PO-351, 353, 355 & 356.

I took it back to the mechanic, he asked me if I was afraid I would get stuck. The car has never stalled so I told him no. He erased the codes & told me to drive it until the Light comes on again. Naturally, the car is running perfectly. I don't know what to think but I do want it fixed.

Any ideas? Thanks for reading.
 

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"all 6 coils couldn't go bad at once" = good thinking
So did he end up replacing the intake manifold gaskets? I don't see how this would fix an ignition coil code. Sounds like he needed to come up with something he knew how to do and charge you for it.

Sounds like some kind of wiring issue or a PCM problem. Perhaps some kind of widespread electrical problem (battery or alternator)?

Have the spark plugs ever been changed on your car?
 

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Discussion Starter · #3 ·
The battery was replaced in May of this year & the terminals are clean.

I bought the car 5 years ago with 95,000 miles on it. The original owner put 90,000 miles on the car in 18 months. Yes, you read that correctly!

The 2nd owner purchased it after it sat around for 6 months. She had new tires, battery, tune up, etc. In the 5 years I've owned it, this is the first repair I've had to make.

My Wife drives it 90% of the time, all local short trip driving. When I drive it on the highway I usually try to "punch" it once in a while.

I know that's not much help but that's all I've got. Thanks for the reply.
 

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Well, here's what I would check. Just for fun check the battery voltage. It should be 12.6 if fully charged (you can use ETM if you don't have a voltmeter - http://www.taurusclub.com/forum/82-...9931-experimenting-engineering-test-mode.html). You should get 14 volts with the car running. I know you just replaced the battery, but I want to rule it out.

Hopefully they replaced the spark plugs with the 90k tune-up. In 43k they should be good still, but I might pull one spark plug just to make sure. Carefully check the gap and look for any other problems. Did your mechanic check the plugs?

I would also inspect the wiring harnesses that carry the COP ignition wires for signs of damage or chafing. Sometimes mice cause the most annoying intermittent problems when they partially gnaw a wire.

Finally, I wouldn't rule out taking it to a Ford dealer and having them do a PCM flash. Sometimes these bugs are fixed with later calibration updates. I know Ford had some trouble early on with the COP modules.
 

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12.31 volts is only about 45% charged. Put it on a battery charger until it's fully charged then check it again in 24 hours to see if it holds it's charge.
 

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Discussion Starter · #8 · (Edited)
First of all the Engineering Test Mode is really neat. Most of the stuff, I don't know anything about but still fun to look at.

I charged the battery for about 5 hours yesterday. The charger started out at 6 amps then went down to less than 1 amp in about 4 hours, I left it on for another hour just to be sure.

15 minutes after I took it off the charger the battery read 12.95 Volts. The car sat for about 20 hours, I checked the voltage & it was 12.34. I also tried the "ETM" and it kept going back & forth from 12.3 to 12.4. So I'm sure the reading is correct.

Now where do I go from here? Is there something draining my battery?
 

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load test the battery. autozone and others do it for free. there is always a drain on the battery because of kam feature. ( keep alive memory ) an older/weak/bad battery cant handle the drain and loses to much power to fast. having the battery tested is the easiest test to start. there are batteries that only last 6 months or less because of a problem from the factory or other reasons. this is why they give you a warranty
if battery test good then its possible you have a relay stuck or something else.
 

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No, those voltages are correct!
12V after it sat long time, 13V right after charging, 14.2V alternator charging...

Probably you have a weak ground commun to the coils or the manifold is not tight enough on gasket (too lean and will miss the ignition), or even a EGR or PCV valve that "hangs" some times...
It is an intermitent condition.
Obviously, even if there was a slight possibility that all the coils decided to go bad at one time, there is none that all of them decided to repair themself after that :)
 

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No, those voltages are correct!
12V after it sat long time, 13V right after charging, 14.2V alternator charging...

Probably you have a weak ground commun to the coils or the manifold is not tight enough on gasket (too lean and will miss the ignition), or even a EGR or PCV valve that "hangs" some times...
It is an intermitent condition.
Obviously, even if there was a slight possibility that all the coils decided to go bad at one time, there is none that all of them decided to repair themself after that :)
right the numbers are correct. but the battery showed low in the above post. I should ask how long was the car sitting before you tested when you got the low voltage?
 

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Discussion Starter · #12 ·
When the battery had 12.31 volts it was only sitting overnight.

I replaced the PCV Valve in May of this year when I replaced the Battery, just coincidental. Previous to that my Wife was driving the car. She called to tell me that the ABS Light & Battery Light went on while driving. She pulled in a shopping center parking lot & let the car idle. The car never stalled, ran rough or anything. She turned it off, restarted the car and no ABS or Battery lights on. She drove home (about 5 miles) with no problems.

I came home from work, checked the voltage on the Battery it was 11.98. I cleaned the battery terminals & charged the battery overnight. The next morning after starting the car, I checked the charging system. The best I could get was 13.7 Volts with / without the lights, AC on, etc. That was probably mid-March.

Then one morning in May I just got the clicking when trying to start it. This time I checked each cell with a Hydrometer, the second cell on the Positive side was lower than the others. I took it back to Autozone since it was less than 2 1/2 years old & replaced it.

It has been fine until this episode. It has me stumped???????
 

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have the battery and alt load tested at the parts store. make sure you have the lights, a/c and radio on. low voltage causes issues with the taurus and its a free test. also take a look at the distribution block connections and make sure there are clean. as far as the coils. there is a test for them. you can find it in the topic finder with the specs.
 

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Discussion Starter · #14 ·
Some interesting info thanks to Behlinla telling me how to use the "Engineering Test Mode".

A January day in late October. Rainy, occasional slush & down right chilly. I went to visit my Dad in the hospital. With weather like today the defroster (which runs the AC compressor), rear defroster, headlights, wipers, CD player were all on. As big a drain as you could possibly have on your battery.

The car starts up fine & is running fine as usual. I noticed as I came to a stop the CD player shut off for a second or 2. This get more & more frequent during this 5 mile ride. The car actually hesitated when I accelerated after stopping at a traffic light. I got to my destination, turned the engine off then got it into the Engineering Test Mode (ETM). The battery at rest registered 12.1 Volts. I started the car & stayed in the ETM and I had 14.3 Volts.

When I left the hospital (about 1 1/2 hours later), I had the bright idea of driving the car home in the ETM. I had it set on battery.

When just driving along at 30 MPH the Voltage maintained 14.3 Volts +/-. When coming to a stop the Voltage was all over the place (11.6 to 14.3). At one time the CD Player went off the Voltage was 10.9. The car has always had a very low idle speed, about 600 RPM's in drive when warm. Between 800 to 1000 RPM's in Park. When the Voltage dropped to 10.9 I thought the car was going to stall. I hit the gas a little with my foot on the brake, I was at about 1000 RPM's and back to 14.3 Volts.

Does this mean the Alternator/Regulator is going bad? I have not had a chance to go to Autozone yet to get the charging system checked.

Has anyone come across anything like this before? Any help would be appreciated. Thanks!!
 

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Great troubleshooting. I'm really glad you were able to use ETM while driving to monitor the voltage situation. That's one reason I really like it (and wrote about it)!

I think the alternator is working fine. With everything on in the car, the load on it is more than it can handle at idle. When this happens the battery is supposed to provide the rest of the required energy at idle if the load it more than the alternator can produce. Once the engine speeds up a little, then the alternator has enough rotational energy available and it can keep up. This is evidenced by the fact that the alternator is always keeping a fairly steady 14.3 volts when the car is moving at speed. If the regulator or brushes were bad, you would either not see full charging (14 volts or more) or the charging voltage would be all over the place when driving at a constant speed.

Right now all signs point to a bad battery. It's supposed to maintain 12 volts or more at all times. It sounds like your car is running almost exclusively off the alternator. As you can see the engine does not like to run on less than 11 volts. I can't say for certain the battery is the cause of your coil codes, but if they aren't getting enough voltage they probably won't work too well. Like everyone's saying, you need to go and get the battery load tested and have them check the alternator as well. Bad batteries put a big strain on alternators so you should get it fixed sooner rather than later to save yourself the $$'s.

If you do get a new battery, have the store load test it to make sure it's a good one. Since the car is used for short trips, in the future it might be wise to invest in a trickle charger you can put on the battery every so often (like on the weekends). This should extend the life of the new battery significantly.
 

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Discussion Starter · #16 ·
Thanks a lot for all your help. One more question, if the problem is the battery (which makes sense) would a bad cell show up with a Hydrometer test? I will take it to Autozone for the load test but I am just curious.

Once again, thank you!
 

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Thanks a lot for all your help. One more question, if the problem is the battery (which makes sense) would a bad cell show up with a Hydrometer test? I will take it to Autozone for the load test but I am just curious.

Once again, thank you!
Hyd test may and may not show low with a bad cell.
If there is a broken connection, it may be OK but just have resistance under load.

If plates break while in the part discharged state, then the sp G. cannot be brought up.

Worth a try to check it with a Hydro. If any cell is well below the others, then replace the battery.

If all nearly the same, then a load test is worth the drive.

-chart-
 

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I've had several batteries in the last few years with bad internal connections in the battery.
No cranks, smack the battery and headlights come on and cranks right up.
Intermittant flickers in the headlights at night started before the no crank issues came up.
Battery load tested OK at AZ when carried into store. Had two of them do that.
 

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a float charger is better then a trickle charger. get one that you bolt the connection permenently to the battery and plug in when needed.
 

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a float charger is better then a trickle charger. get one that you bolt the connection permenently to the battery and plug in when needed.
Whoops, ment to say float charger/automatic battery maintainer. :blush: Trickle charger just happened to pop into my head when it wrote it...

If you have a battery hydrometer go ahead and check the cells if you want. Add distilled water if they're low. It might or might not make a difference. The battery seems to have a high internal resistance for some reason (failing connections, low electrolyte, sulfated plates etc.).
 
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