2007 Ford Explorer Limited V8 3 valve ignition problems

Hello guys (and gals), I have written about this issue in the past and I thought I had it cured, but apparently I did not. hang on for this ride....

I had a problem that started at about 60k and it was a miss that developed on the way home from a long, long drive. I removed the spark plugs and cleaned them checked the gap and threw them back in and the problem was gone. I purchased replacement plugs (Motorcraft) the very next morning threw them in and was good til about 80k when the engine started missing again.
I cleaned the plugs, re gapped them and threw them in and the problem was gone. I let it go till about 90k when the problem came back. I changed the plugs again and the problem was gone till about 115k. I replaced the plugs and the problem was gone. The problem came back at 125k and this time i replaced all the ignition coils and spark plugs once again. Now I am at 139k and after a 2 hours drive the problem has returned. I pulled the plugs and cleaned them although they were clean, cleaned the new coils and put them all back on and the problem is NOT going away anymore. Compression is good and even on all cylinders. No contamination in the oil or antifreeze. The plugs are clean as well.
I hooked up my crappy CanOBD2 meter and pulled the code for "random missfire". (P0300 Diagnostic Code - Random Misfire)

I am not sure what to check next as I do not have a diagnostic tool that can check "Mode 6".
Any advice would be greatly appreciated.

Anyone? Maybe I should bring it to Ford (Lord help me) and let them scan it further.

If it's missing consistently, you can determine which cylinder by disconnecting coils one at a time till the RPM doesn't drop. But, I'd be looking at the connector(s) that supply voltage to that coil or injector. Trace those wires and clean all connections. I'd use CAIG DeOxIT D100 (not tuneup grease).

Not sure if that will help, but since my first replacement of plugs after a very bad misfire at 100K, I replaced them already 3 times due to the same symptoms like yours - except every time I was getting 308. Finally I figured it was # 8 that was crapping on me all the time due to the water dripping on it. But every time I replaced all 8 and it was good for 10-15 k miles. Now at 160k all is good after I installed a little water gutter under the windshield.

Ornery said:

If it's missing consistently, you can determine which cylinder by disconnecting coils one at a time till the RPM doesn't drop. But, I'd be looking at the connector(s) that supply voltage to that coil or injector. Trace those wires and clean all connections. I'd use CAIG DeOxIT D100 (not tuneup grease).

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I did pull all the coil connectors as well as the fuel injector connectors, but the engine management system seems to try to compensate and it makes it very difficult to hear any difference. I also did the same test under load with my wife holding the rpm's at 1k with foot on brake in gear. Same problem almost impossible to detect difference. In neutral the engine seems smooth, but put it in gear and it shakes like crazy. Plus I can hear the miss out the exhaust. I already used dielectric grease on the connectors..I'll try your recommendation in the future.

Explorer_PL said:

Not sure if that will help, but since my first replacement of plugs after a very bad misfire at 100K, I replaced them already 3 times due to the same symptoms like yours - except every time I was getting 308. Finally I figured it was # 8 that was crapping on me all the time due to the water dripping on it. But every time I replaced all 8 and it was good for 10-15 k miles. Now at 160k all is good after I installed a little water gutter under the windshield.

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I read about this issue, but never had that problem with mine. The plugs are always dry even after a heavy rain storm. Seems it is pretty sealed for now, but I will keep an eye on it. Thanks

Never mind ... Ornery already covered what I had typed so +1 for checking the 12V connectors including tracing the wires to make sure there are no breaks/cuts in them.

I don't specifically mean the connectors right on the coils or injectors (though it wouldn't hurt to clean them up), but where those connections are made to the computer. No, I don't know where that happens on an Explorer, but on my Panther cars, there's a connector block under the brake booster that goes through the firewall to the module. That connector has MANY connections that all have to be good. Simply unplugging it and plugging it back in a few times might do the trick... for a while. That's where a good Spray De-oxidizer and then Protectant (like tuneup grease) does the trick.

Edit: Took picture of it.



Don't know which connector handles the coils and/or injectors, but you can probably figure it out by the colors. Probably want to disconnect the battery before screwing with either one.

Ornery said:

I don't specifically mean the connectors right on the coils or injectors (though it wouldn't hurt to clean them up), but where those connections are made to the computer. No, I don't know where that happens on an Explorer, but on my Panther cars, there's a connector block under the brake booster that goes through the firewall to the module. That connector has MANY connections that all have to be good. Simply unplugging it and plugging it back in a few times might do the trick... for a while. That's where a good Spray De-oxidizer and then Protectant (like tuneup grease) does the trick.

Edit: Took picture of it.

Don't know which connector handles the coils and/or injectors, but you can probably figure it out by the colors. Probably want to disconnect the battery before screwing with either one.

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Very nice! Thank you and I will check it out.
I brought the truck to the dealership this morning and explained everything I have been doing and he said he would have done the same so he will look for further codes. He called me back and said that replacing the plugs fixed the miss. I told him that I know that , but in 10k it will be missing again. He agreed with me and said he would call Ford direct for further tech support. I will be waiting for his call tomorrow afternoon.

Took my vehicle to the Ford dealer and after they received their call back from Ford tech they were told to replace the plugs and coils...
I know that it will fix the problem. The major problem is that the issue will return in 10k- 15k miles! Plus i already replaced the ignition coils...All 8 of them.
Well anyway they told me that they have no idea what is wrong with my vehicle and after paying them $219.24 cents for diagnosis and a computer module update I still have a serious misfire.

This is the notes that the technician wrote down:

"Test drove the vehicle and verified engine misfire. Perform IDS Diag & found fault codes P1000 & P0316 & P0300. Performed spark duration test, cylinders 6 & 8 indicating high resistance in secondary ignition (spark plugs) Removed plugs to examine. Found aftermarket plugs installed (Champion). Suggest replacing plug with Ford plugs and performing PCM update. Verified this concern with Ford assistance hotline and they suggest doing the same. Mr. Soriero (Me) approved the PCM update and will replace the plugs himself. The check engine light will stay on until the spark plugs are replaced."

I replaced the plugs when I got home tonight. I reset the codes and disconnected the battery to make sure all is clear. I started the engine and drove from my driveway. At idle the engine is running smooth, however when accelerating the engine is still misfiring. The coil packs are all less than 10k miles on them. Could they be bad already? I found the connectors into the ECM and cleaned them thoroughly. They were already very clean. Cleaned every other connector I could find and the misfire remains.
I have no idea what to do or where to take the truck since the Ford dealers can't figure this out. Maybe the crank trigger? Although that should have tripped a code if it were that... I am lost on this one and running out of money and patience with this vehicle.

With the exception of changing plugs (should have used OEM), you've just been throwing money at the problem. With proper diagnosis, that money could have been used to buy the correct part, which may turn out to be the Powertrain Control Module. The Service Manual will have step by step procedures to track the problem down to a component or bad connection. Might even be a frayed wire (inside the wire jacket) from the coil to the PCM. An ohm meter could pinpoint that.

The fact that you have two circuits involved makes that seem unlikely. Can't believe what dealers charge for this "service", and to misdiagnose it is just insult to injury. If you do need a PCM, they're going to have to program it, so maybe they'll give you a break since they dropped the ball. Anyway, find a REAL mechanic who can troubleshoot this properly. Obviously, the dealer ain't him!

Ornery said:

With the exception of changing plugs (should have used OEM), you've just been throwing money at the problem. With proper diagnosis, that money could have been used to buy the correct part, which may turn out to be the Powertrain Control Module. The Service Manual will have step by step procedures to track the problem down to a component or bad connection. Might even be a frayed wire (inside the wire jacket) from the coil to the PCM. An ohm meter could pinpoint that.

The fact that you have two circuits involved makes that seem unlikely. Can't believe what dealers charge for this "service", and to misdiagnose it is just insult to injury. If you do need a PCM, they're going to have to program it, so maybe they'll give you a break since they dropped the ball. Anyway, find a REAL mechanic who can troubleshoot this properly. Obviously, the dealer ain't him!

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I used OEM many times in the past and the problem was still there. I used an ohm meter to compare resistance on Champion, Autolite, and motor craft plugs and they share identical resistances. ( I have many plugs since I tried almost all brands). The Champion plug is also a one piece body plug which to me makes it stand out as a better plug, but either way I put the motor crafts back in. I believe they are all platinum tip and the Autolite uses a "U" gap instead of "J" gap.
The only reason that i threw money at it was because my OBD2 meter reader could not check individual cylinders. Also, because the mechanics (Ford) dealers near me are truly incompetent. They are parts changers as I resorted to being. It won't happen again. I have many visits to the local Ford dealers (4 right near me) and every visit cost me a ton of money without the vehicle being repaired the first time. I am going to get a better OBD2 meter...Any ideas on one?

UPDATE*
I watched a youtube video to which a mechanic tested each cylinder under load while running. He pulled each coil wire (which I did too, but the difference was almost undetectable. The difference was that he also pulled the air tube off the throttle bode and disconnected the air flow sensor. Now when I pulled the plug coil wires it made a world of difference. I found the number 6 cylinder making little to no difference when I pulled the wire. I pulled that coil and put a spark tester on it and to my surprise it would only spark when the gap was about .020" I grabbed one of my old coil packs tested it and found it would jump almost a half inch gap! Blue spark!. I tested all the rest of the coils and found that they all make a very weak spark. Ordered new coils (again) and will be returning the bad ones.

UPDATE AGAIN*
I am very disappointed to say that now the engine running on 8 cylinders, but...there's always a but, anti freeze is now running out my exhaust again. There is no anti freeze entering the cylinders or the oil. It seems to be getting in the exhaust bypassing the cylinders. I am at a loss on this one as I do not know the modular ford engine very well. I am trying to figure out the coolant flow and jackets. Could it be the intake or EGR system somehow? I will revert to my prior post on this one. Thanks for all the help to those that contributed.

Wow, an almost happy ending! Do appreciate the updates. I was referring to ohm testing the wires from the coils to the PCM. Thanks for the info on removing the air tube and disconnecting the air flow sensor. Great tip!

I used to throw parts at these issues. Not a big deal when you're taking care of normal maintenance items, but I'm too poor now to spend anything unnecessarily. I'm afraid to ask what brand coils you used. I've kicked around buying the $8.00 Ebay units. As it is, I save my old coils and use them on occasion.

I only know of one way coolant could get in the exhaust. All I can say on the plus side, is this may be a good time to also address the exhaust manifold gasket leak issue...

Ornery said:

Wow, an almost happy ending! Do appreciate the updates. I was referring to ohm testing the wires from the coils to the PCM. Thanks for the info on removing the air tube and disconnecting the air flow sensor. Great tip!

I used to throw parts at these issues. Not a big deal when you're taking care of normal maintenance items, but I'm too poor now to spend anything unnecessarily. I'm afraid to ask what brand coils you used. I've kicked around buying the $8.00 Ebay units. As it is, I save my old coils and use them on occasion.

I only know of one way coolant could get in the exhaust. All I can say on the plus side, is this may be a good time to also address the exhaust manifold gasket leak issue...

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Thank you for the info!
Here are the coils I used that failed: http://www.summitracing.com/parts/GRN-25-3001

I will be returning them and they are replacing them with Accel units.
As for that video. Wow! That guys is nutz , but good. I am not a fan of using fixes ion a bottle, but in desperation I have used Barsleak to get home.
Ford mechanic actually called me to ask how the vehicle was doing and I told him what happened and the leak and all. He thinks it may be a cracked head or block. Seems to be no way antifreeze can get past the cylinders before coming out the exhaust. I just don't know.
Quoted me a price of round 4k to do a head gasket job. If the motor is cracked it will be significantly more money.

UPDATE*
I'm a dope. let me explain. I have been a Marine mechanic for almost 35 years and have worked on almost every engine you can imagine. I built racing engines in the 70's through the 80's both automotive and marine. I always prided myself on being very good at diagnosing problems of all kinds. Somewhere along the line on this one I screwed up and missed the obvious. I decided once again to pull the spark plugs and oil refill cap, pressurize the coolant system to 15psi to make this leak very evident and maybe I could even hear it. I did and the pressure dropped while anti freeze now poured out the exhaust. I cranked the engine to hopefully see a spray of antifreeze or see pressure in the oil galley. Nothing!
I noticed heater hoses running to the rear of the truck. I asked myself why would heater hoses run to the rear of the truck and not to the heater coil in the firewall. Well they run both ways. The truck has a rear A/C and heater unit. I never knew this. The rear heater unit is right above the tail pipe and is leaking at the fittings. It leaked right into the tailpipe and then runs out. I had no reason to lay down and look above the pipe since I did not expect heater hoses to be there. Wow! What a relief! Now I just have to hope the ignition system is repaired as well.
So far so good...for now.

thanks.

Holy crap, that "Steel Seal" would have had a helluva time fixing that!

That is great news. Now, I'll be aware of issues that can crop up at the other end, too. Sheesh, screwing with the A/C back there must be a pill.

My only claim to fame is keeping old Fords on the road way beyond reason.



Three of those vehicles are still daily drivers, though two are really just winter beaters now.

And, now you can enjoy your ride for a while. Happy motoring!

Ornery said:

Holy crap, that "Steel Seal" would have had a helluva time fixing that!

That is great news. Now, I'll be aware of issues that can crop up at the other end, too. Sheesh, screwing with the A/C back there must be a pill.

My only claim to fame is keeping old Fords on the road way beyond reason.

Three of those vehicles are still daily drivers, though two are really just winter beaters now.

And, now you can enjoy your ride for a while. Happy motoring!

Click to expand...

Yeah the older vehicles I can handle.
Happy motoring to you too.
Thanks!

Update*
I called Ford about replacing the rear unit's heater hoses which are basically formed "U" shaped hoses held with spring loaded style factory clamps. The one clamp rusted and broke and damaged the hose causing the leak. The hose is about 6"-8" long.
The Ford parts guy told me that the hose only comes with the aluminum pipe that runs under the truck all the way to front of the vehicle. Each one lists for $290.00. I almost fell off my seat!
I said the heck with that and I removed the hose and cut off about 3/4" where the hole was and reattached it with a worm style clamp (stainless steel). I pressurized the coolant system to 15psi and it held with no leaks. I topped off the system with anti freeze and ran it to operating temp and it ran flawlessly with no more leaks. YEAH! (so far.....)

Finally some good news. It should hold. I love the "real mechanic" solutions where for few bucks you fix a problem that would cost few hundred from the dealer. Just by being creative, unlike too many today's mechanics just replacing parts.