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Discussion Starter #1
Hello, all. Like so many of us, I get an intermittent fault code for misfires. This weekend, I am going to replace my coils and plugs. If that does not eliminate the misfire, then i will turn my attention to the injectors. I notice that the part I need, if I remain with OEM, is the Motorcraft 5212. I have noticed that Bosch also makes an injector that will fit, and I see that there are some other brands. Should I stick with OEM or are there better injectors for completely stock applications? The only performance upgrade that I foresee would be getting the Cobb Accessport, so I won't need additional fuel delivery, etc.
 

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How many miles? You might not even have to replace the plugs. You might just have bad gap on your plugs and need to re-gap them. Get a set of check gauges and check the gap first. Should be 0.026-0.028". I think Ford has a wider range fro stock, but that gap is what most of the tuners recommend. This car is notorious for plug gap creeping resulting in misfires.
 

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I agree with check the plug gap first. I go a cyl 2 misfire a few months back and the first thing I did was pull my current ones and check the gap. They were all up around .029-.032. Took them all down to .025 and haven't had a problem since. Whenever you have to buy plugs that are engineered for a larger gap than you need and have to close it, repeated heating and cooling of the ground strap causes the gap to open back up naturally over time.
 

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Discussion Starter #4
Thanks for the replies. I understand about plug gap, and what happens over time. But if I don't get satisfactory results, does anybody have opinions on which injectors are best for a stock engine? Motorcraft or something else?
 

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I went through a similar situation last month. Had lots of misfiring on idle and cyl 1 misfire (warm or cold starts). Fixed my gaps, replaced plugs, moved coil packs then plugs. Had good compression on all 4 cyls and removed my tune. Still the misfired continued. Took off my intake manifold and had lots of carbon buildup. Got it all cleaned out last weekend and that did the trick.

I'd check your valves before buying new parts.

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Discussion Starter #7
I have a little over 58,000 miles on it at this point. I'm going to go through a few of these things, one by one, until the problem is resolved. I am mostly curious, though, about brands of injectors. Doesn't anybody have an opinion about them?
 

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Out of curiosity what exactly is happening with the misfire? When the engine is cold, hot? Under light throttle, full throttle, cruise or idle only? Any stalling? Any foul exhaust smell? Any stumbling after you fill up?

Even more important, what CEL codes are you getting?

Truthfully I don't think plugs, coils or injectors are your issue. I changed my plugs at 60k and they were definitely gapped too far, but they didn't cause the car to run rough. If you are having a full time misfire you can unplug each coil individually and see if you find a cylinder that doesn't react. Injectors aren't a common item to fail. A LOT of people have fixed this with either the emissions hose or evap check valve near the gas tank.
 

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I went through a similar situation last month. Had lots of misfiring on idle and cyl 1 misfire (warm or cold starts). Fixed my gaps, replaced plugs, moved coil packs then plugs. Had good compression on all 4 cyls and removed my tune. Still the misfired continued. Took off my intake manifold and had lots of carbon buildup. Got it all cleaned out last weekend and that did the trick.

I'd check your valves before buying new parts.

Sent from my LG-H872 using Tapatalk
AGREE!

I just put a can of CRC valve cleaner through my car... best $11 I have spent. HIGHLY recommend it to anyone over 20k on the car. I have 66k and I am going to be doing it in the next 10k and start doing it every 10k

I have a little over 58,000 miles on it at this point. I'm going to go through a few of these things, one by one, until the problem is resolved. I am mostly curious, though, about brands of injectors. Doesn't anybody have an opinion about them?
no one has replaced them because NOT the issue

If you are willing to replace injectors then pulling the intake manifold and check valves should be a simple task. Do it and report back with you finding of carbon build up and how many miles you have.

While you are in there check the plug gap for fun as well. .028-.030 for a stock car -- or .026 tuned or what ever your tuner suggests

Guessing injectors are good for 200k+ on these cars. I have not heard of any one having an issue.
 

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I had my injectors replaced by Ford under warranty.

Car was throwing cold start misfire codes. Ford didn't really know what to do so they just started throwing parts at it. They initially just replaced 1 injector (said it was fouled) and when my check engine light came on shortly after that, Ford authorized them to replace the other 3 injectors too along with all 4 spark plugs.

Went through the winter without an issue (idle still sucked, but no codes were thrown), but once it was a little warmer outside, the check engine light came back for misfires on cold start.

So, based on my experience, the injectors were never the issue for misfires.
 

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Discussion Starter #11
I haven't experienced the CEL on startup or while idling. I seem to always get it when I am in a higher gear (5th or 6th) and at low RPMs and then I open the throttle to accelerate. I recently ran Techron in a tank of gas, but I haven't pulled the intake manifold and cleaned anything yet.
 

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Discussion Starter #12
Ok, so if I have to end up pulling the intake manifold, what's the difficulty level on these cars? I haven't pulled an intake manifold in quite a few years.
 

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Ok, so if I have to end up pulling the intake manifold, what's the difficulty level on these cars? I haven't pulled an intake manifold in quite a few years.
Its super easy. 5 bolts on the front and its off.

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Discussion Starter #14
Thank you. I also found a step-by-step tutorial and it definitely doesn't look bad! Is this enough to get the valves really clean if they are caked with carbon? When might I need the walnut shell blast cleaning that some friends with DI engines have needed?
 

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Thank you. I also found a step-by-step tutorial and it definitely doesn't look bad! Is this enough to get the valves really clean if they are caked with carbon? When might I need the walnut shell blast cleaning that some friends with DI engines have needed?
https://www.amazon.com/CRC-05319-Intake-Valve-Cleaner/dp/B00PHNQKR2

Personally much the easiest way to clean valves.

Recommend removing your intake manifold. shining a light and checking the status of the build up. then running a can of that through the intake. see before and after results.
 

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Discussion Starter #16
I replaced my coils and plugs today. Here's what the plugs looked like:

IMG_20180406_192350.jpg
IMG_20180406_192533.jpg

The plugs were all gapping at about 0.032+.
 

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Discussion Starter #17
I need to find an intake manifold gasket and then I'll also clean the valves. Any recommendations for a place to get one?
 

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The safe way (when done properly) to clean valves on this engine is a walnut blast.

If you have severe carbon breakup and you run a cleaner through the intake to break the carbon up, it's going straight into the combustion chamber as debris.
 

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I need to find an intake manifold gasket and then I'll also clean the valves. Any recommendations for a place to get one?
Doesn't have or need a gasket it has a rubber seal. I have taken mine off and on countless times now owning the car and have had no issues nor replaced any seals.

The safe way (when done properly) to clean valves on this engine is a walnut blast.

If you have severe carbon breakup and you run a cleaner through the intake to break the carbon up, it's going straight into the combustion chamber as debris.
true, but at the same time, not a big deal. guess it would depend on how "severe carbon" is. I have 66k on my car and compared to pictures online I would NOT have called my buildup as "severe". So I ran a can through my car and honestly it is barely cleaner than before, cleaner but barely, I have to look at the pictures side by side to see the slightest difference. In other words I don't think chunks that will damage anything are going to come off.

I am going to start running the cleaner at each oil change and keep checking the valves, hoping they look "new" some day again.

that debris will just blow out the tail pipe, really cant imagine it being an issue. but maybe someone has blown up an engine running this cleaner? youtubers are a dime a dozen these days
 

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Discussion Starter #20
My brother in law, who is a master mechanic and who worked for Ford for many years, explained the way he'd prefer to do it. He likes the idea of spraying SeaFoam or other intake valve cleaner *VERY SLOWLY* into the intake. He recommends a rate that would spend the entire can in about 45 minutes, rather than the repeated 30-second burst method. And you'd keep the RPMs up at around 1500 for the duration. He said that if it takes you 10 minutes to empty the can, it will not do any good at all. He has used this (slow) method before and used a snap-on professional grade endoscope, and said that the valves looked like new after doing it. I don't know of a really good way to be able to regulate the flow of the can to a rate that slow, but it might be a good way to do it.

I haven't heard of this super-slow method on the forums before, and since my brother in law is a professional, I thought I'd repeat what he said here. I might still decide to pull off the manifold, though, so I can see what I'm doing.

My issue is that I haven't seen any really good guides on how to remove the manifold. I found a guide, but I didn't think it was very good. Any suggestions?
 
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