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brentagade

Troubleshooting misfire on 2012 5.4 3V

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Greetings everyone. New to the group. I'm looking for some assistance in troubleshooting. I have a 2012 XLT EL, 5.4 3V, with about 101k miles. It's been running like a top up until about a month ago. It started running rough and eventually began misfiring. I used to have a 2002 F150, so in my experience it was a bad ignition coil. I got the code read to find out which one and it returned 0430 steering me toward possibly O2 sensors or Cat.

As I was contemplating what to do I went and go the oil changed and had them read the code again. This time it returned additional codes of 0300 and 0307: Random misfire and #7. That helped me narrow it down (I thought) and would fix the 0430 code possibly too. Because of the mileage, I was just going to do all the plugs and ignition coils myself. I spoke with 5 different people/mechanics and they all gave me the horror story of 2 piece plugs and to not change them myself.

So I took it to the stealership and let them rake me over the coals to swap out all the plugs. Of course they always come back with more, but I wasn't prepared to sacrifice my first born for new ignition coils at this time so just paid for the plugs. They said Bank 2 cylinders were showing between 1-3% compression change.

I went to Autozone, got a whole set of Duralast coils and changed them in 20 minutes. The truck ran fine for about 2 miles and began missing again. "Son of a .....". So I got the codes read again. This time 0430, 0300, and 0306....#6....WTF? So I though, maybe I got a defective coil in the set of 8. I went back to Autozone and used the warranty to swap it out. Ran "ok" on the way home. Next morning, missing again on the way to work. Ugh.... Soooo...I've had new plugs replaced by the stealership and all new ignition coils and still misfiring. I'm stumped. Could this possibly be an electrical issue with the wiring and signal??? Please help.

Thank you much.

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Ok first by most 2009s the plug issue has been fixed. You

Should have changed them your self. At any rate. Its possible you have a bad spark plug. They could have cracked or dropped it before installing it. How much did they charge you to change them? I would grab a new motorcraft plug and change it on #6 or whatever misfire is showing. Without any diagnosis equipment its hard to be exact on your issue but I would replace the suspect plug and try again. The p0430 is more than likely a bad catalytic converter on bank 2. However, wont cause anything but a check engine light. Get it running right and then revaluate.

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Thanks. Unfortunately at a "few dollars off", out the door, they charged me about $468 to change 8 plugs....what a crime.

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Seems a little high because those plugs dont break.

However,:

Repair pal states.

The average cost for a Ford Expedition Spark Plug Replacement is between $348 and $487. Labor costs are estimated between $264 and $333 while parts are priced between $84 and $154. Estimate does not include taxes and fees.

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So after driving the truck back and forth to work today, I checked the codes again when I got home. It added 0307 for cylinder #7. So it's not just the one cylinder....

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Sometimes misfires confuse the pcm and dont always flag the correct cylinder. Does your scanner let you look at obd2 mode 6? Or do you have access to a scan tool that will do power balance?

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Greetings everyone. New to the group. I'm looking for some assistance in troubleshooting. I have a 2012 XLT EL, 5.4 3V, with about 101k miles. It's been running like a top up until about a month ago. It started running rough and eventually began misfiring. I used to have a 2002 F150, so in my experience it was a bad ignition coil. I got the code read to find out which one and it returned 0430 steering me toward possibly O2 sensors or Cat.

As I was contemplating what to do I went and go the oil changed and had them read the code again. This time it returned additional codes of 0300 and 0307: Random misfire and #7. That helped me narrow it down (I thought) and would fix the 0430 code possibly too. Because of the mileage, I was just going to do all the plugs and ignition coils myself. I spoke with 5 different people/mechanics and they all gave me the horror story of 2 piece plugs and to not change them myself.

So I took it to the stealership and let them rake me over the coals to swap out all the plugs. Of course they always come back with more, but I wasn't prepared to sacrifice my first born for new ignition coils at this time so just paid for the plugs. They said Bank 2 cylinders were showing between 1-3% compression change.

I went to Autozone, got a whole set of Duralast coils and changed them in 20 minutes. The truck ran fine for about 2 miles and began missing again. "Son of a .....". So I got the codes read again. This time 0430, 0300, and 0306....#6....WTF? So I though, maybe I got a defective coil in the set of 8. I went back to Autozone and used the warranty to swap it out. Ran "ok" on the way home. Next morning, missing again on the way to work. Ugh.... Soooo...I've had new plugs replaced by the stealership and all new ignition coils and still misfiring. I'm stumped. Could this possibly be an electrical issue with the wiring and signal??? Please help.

Thank you much.

What I would do first is buy some dia electric compound take each coil out and dab each connection point with the stuff. You can buy a replacement pack of coils for $40 also. I've done this and find it works, the engine comes back good as new. I was getting oxygen sensor codes, also I replaced them (you need to buy the special tool for it and spray them with PB 3-4 days before you plan to do it). However - not only will adding dia electric grease resolve this issue - if you're truck isn't having issues do the same and I suspect you'll notice a difference. I had one bad coil which I replaced along & put on the compound, however while I was at it did 3 of 4 on the passenger side throttle response was as strong has I can ever recall it being. I am thinking that rather coils actually going bad - the dia electric compound often needs to be applied. I have a buddy with a Audi that is always replacing coils - all four each year after the car turned six years old. I mentioned my theory on the dia electric compound and he was able to get away without replacing the coil the last time. I suppose that the compound simply heats up and either evaporates or runs away.

 

Also do the homework and find a non-dealer mechanic in your area people trust, I bought my truck used and had such a garage do my plugs at 100k - had no issues. I moved away and foolishly took my truck to the dealer for the next issue - a coil as it was bill was $600. (Which I found out later costs $80 for the Ford part and the procedure to replace one takes at most thirty minutes) after that it seemed like I had something going wrong about every 4 months, minimum I'd pay was $600. I finally took my own medicine and found a recommended local garage - the 4 month cycle disappeared immediately, and bills were in the $200-$300.

Edited by meyeste

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Interesting how its a "stealership" employee (Fordtech1) who is willing to help you...

 

You may have to get MPLRN reset. Usually to work on the passenger bank, the PCM gets removed to gain access to change the coils and plugs. It SHOULDN'T lose its MPLRN values, but in case, you need to accelerate to 55mph then decelerate to the mid 30s a couple times, climate control off and no brakes and no throttle. Otherwise, you still probably need something as Fordtech said, that can watch power balance and Mode 6.

Just because plugs are new doesn't mean they are good. They have been shipped, dropped, kicked, and who knows before they got on the shelf at the DEALERship. And Unless they're Motorcraft, I wouldn't trust a parts store coil. Finally, if you messed with the injector connectors at all, check that they are plugged all the way in and latched. Injector connectors are easily broken, and unless they are completely plugged in and latched, they can make very intermittent connection that can potentially NOT set a code.

Edited by YT90SC

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So it's been a few weeks, but I thought I should give you all an update. The problem WAS the catalytic converter on the driver's side. I got in with a mechanic and he was troubleshooting the plugs, coils, and fuel injectors. They couldn't figure it out until he took it for a drive. Came back and dropped the cat. It was completely demolished inside. It came all apart and there was virtually no flow through. He put a new one on in the morning and that was it. It's been running great since. Of course it cost me twice as much since I already had replaced everything else first, but hey, I'm back on the road. Thanks for all the help.

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