Cylinder 1 Misfire. NOT plug,coil,or injector. Help

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BrinkExpo

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Hey guys I am getting a misfire on cylinder 1 on my 06 expo with 160k miles. The local Ford service manager and I went for a drive with his computer hooked up to find that it was cylinder 1 because it was not throwing a code.

It only does it around 3,000RPMS and up. We tried swapping coils and it stayed on cylinder 1. We swapped cylinder 1 plug thinking maybe it was overtightened and porcelain cracked but that didn’t fix it.

He also did a test on the injectors and they all read the same.

Now he said to pull the valve cover and check the springs.

Anything else you guys can think of before diving in to that?

Thanks in advance.
 

Adieu

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Hey guys I am getting a misfire on cylinder 1 on my 06 expo with 160k miles. The local Ford service manager and I went for a drive with his computer hooked up to find that it was cylinder 1 because it was not throwing a code.

It only does it around 3,000RPMS and up. We tried swapping coils and it stayed on cylinder 1. We swapped cylinder 1 plug thinking maybe it was overtightened and porcelain cracked but that didn’t fix it.

He also did a test on the injectors and they all read the same.

Now he said to pull the valve cover and check the springs.

Anything else you guys can think of before diving in to that?

Thanks in advance.

Just cuz an injector reads normal resistance doesnt say much about its spray pattern afair
 

Adieu

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Right, so do you think it is more likely an injector or valve springs? Just wondering what to do next?

Well.... An injector costs $35ish. And takes <5 minutes to swap out

Also, you could even just swap it to a different position and see if the miss follows (if you got the obd reader to detect it)
 

rexster314

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My '12 KR had a mystery miss several years ago. Plug, injector, coil were all tested to be ok on cyl. #7. Even replaced them just in case. It would shake like a diesel till the engine warmed up, but still had a miss. Dealer was stumped. One of the dealer's mechanics suggested a pinhole leak in the cylinder head. They removed the head and found rampant corrosion in and around #7 plug hole. We surmised that overnight it would leak down and start up would be really rough. After warmup, engine would settle down with just a slight miss. It was a very slow leak as coolant levels stayed pretty much the same.
 

1955moose

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Like adieu stated pop a new or reman injector in that bank first. Always the easiest and cheapest I was taught in school many moons ago! Come to think of it that pertained to my dates too! But I digress. Usually a failed valve spring, will cause the motor to run on 7 cylinders all the time. 3,000 rpm is a load point of most engines, especially considering our 5.4's start to run out of juice above 5,500 rpm. If you've swapped out the usual culprits on #1 bank, then injector is next logical step. Let us know your findings.

Sent from my N9131 using Tapatalk
 

blue oval guy

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If ignition components are all 100%, you might consider that bank of injectors. The intermittent misfires we have seen here on econoline vans running the 4.6 motor have been injector related.
 

Mike Saunders

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Hey guys I am getting a misfire on cylinder 1 on my 06 expo with 160k miles. The local Ford service manager and I went for a drive with his computer hooked up to find that it was cylinder 1 because it was not throwing a code.

It only does it around 3,000RPMS and up. We tried swapping coils and it stayed on cylinder 1. We swapped cylinder 1 plug thinking maybe it was overtightened and porcelain cracked but that didn’t fix it.

He also did a test on the injectors and they all read the same.

Now he said to pull the valve cover and check the springs.

Anything else you guys can think of before diving in to that?

Thanks in advance.

I had a 2003 with the 5.4 and a similar problem. Dealer ended up replacing the harness for the #1 plug and that fixed it.
 
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