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Ford F150 Pickup: I have a 2002 F150 4.6l with the service

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I have a 2002 F150 4.6l with the service engine light on...truck is idleing and running rough...at times it feels like it would stall but never does.I had the codes read which pointed to the DPFE valve.I changed the valve...it made a small change but still on the rough side..reset engine light but it came on a couple of days later.
any thoughts ..seems to be going thru a bit more fuel as a result of this problem.Thanks...Dan

Ted G. :

More than likely you have a bad coil or coils on the engine. Ford plays a little trick when it sees a misfire on a cylinder. Instead of setting a code and turning on the check engine light, the truck turns off the injector to whatever cylinder is misfiring. Most good techs know how to find the Mode 6 data from the computer, and that will tell them what coil(s) are misfiring. As for your DPFE, most likely the port to the valve is clogged, that can be cleaned with a stiff piece of wire and should get the code to stop setting.


Ted when I pulled the valve there was some fibre like material in one of the lines on the valve


I found some fibre like material (dirt) in one of the tubes on the valve...I had the codes read at the dealer and an auto pro service station..both said the DPFE...neither mention the spark plug coils...are these a big deal to change can I do it myself?


I had the code read at ford dealership and an auto pro service station. Neither one mentioned that the problem could be a coil but was the dpfe sensor. Are the spark plug coils a big deal to change and can I do it myself without taking it in to a dealer?


sorry for the repeat

Ted G. :

I'm surprised that the Ford dealer didn't address your coil/rough running issue. It is not hard to replace the coils but they get kind of pricey. If they were just looking at a fix for the code I suppose they may have disregarded how the truck ran.


should they be able to identify which coil or coils ...should they all be replaced if only one is identified ?...the truck has 209,000 kilometers

Customer: replied 3 years ago.

Hi Ted...not sure if I am supposed to be rating your answer until we are finished discussing the issue...so I will rate your response once we are done


thanks for for help

No problem, I am here to answer your questions until we get your problem solved. (although I am about done for the night, so I may be back on this tomorrow morning)
Customer: replied 3 years ago.

sounds good

Customer: replied 3 years ago.

Hi Ted...I dont see the answer to my last question regarding identification of faulty coils by the code reader or tech...you said mode 6 ...will that mode identify an issue or pinpoint a paticular coil ?...if one or two are faulty should they all be replaced due to the milelage 209,000 kilometers?



Mode 6 can be accessed with a good quality scanner, not a generic code reader. And yes, there is a misfire counter in Mode 6 that will show which cylinders are misfiring, even though it does not set a code. All that said, on any Ford over 120-150km I would recommend doing all coils anyway, other wise you will replace two at a time over the next 30,000km anyway, which can also get pricey. If you shop the coils online you can find some pretty good prices, but as always try and avoid Chinese ones off eBay and whatnot, they are no real bargain.
Ted G., ASE Certified Technician
Category: Ford
Satisfied Customers: 6089
Experience: 20 years auto repair experience, ASE Master Tech, Mechanical Failure consultant, Expert Witness
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Customer: replied 3 years ago.

thank you

Thanks for using our service. Hope we can get you all fixed up. Feel free to return to this thread if you have any follow up questions.
Customer: replied 3 years ago.

Ted...one other thing I forgot to mention because it happens so rarely...on my way home from work today the truck ran smoothly...it will do this occasionaly....would you still think that it is a coil problem....if one was misfiring would it not do it all the time?

Yes, that is possible. The insulation breaks down and will arc more or less depending on temperature, humidity, and load on the system. Many times it will only do it when it rains for instance.
Customer: replied 3 years ago.

during the winter months I remember thinking maybe the problem had gone away because it ran so well...come spring it would sometimes buck like horse....now it is more like the engine hesitating( jerking) but not vilently...I will take it in to get scanned looking directly for a faulty coil....anything else that could cause similar issues?.. ERT,MAF ,O2 sensors....catalytic converter?

While any other cause is possible, I gravitated towards coils because they are consistent with your symptoms and VERY common to fail on that engine. It is certainly the first thing most experienced techs would look for.
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Experience:  20 years auto repair experience, ASE Master Tech, Mechanical Failure consultant, Expert Witness
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