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random miss/stumble, no codes 04 3l 170k klicks

742 Views 12 Replies 4 Participants Last post by  freedom
Wow, researched it & what a possible rabbit hole of possibilities, up to including end of story, 1 was a broke piece of a valve deal.

Due to prior stuff, good bet at least some fuel related issue, possibly fi nozzle issue(s), hopefully not a loose cam cap bolt related

Have had a few prior, usual plug/coil miss related issues & understand now, the dynamics of worn/bad plugs that can fry coils that can then fry a pcm, including cheap coils etc

prior random issues were long cranking starts, smell of fuel, backfire in exhaust on start attempts, a 1 time no start that went ok after a 1hr sit/batt recharge, also had a 1 time oil (using synth) pressure light flicker at warm idle, possibly fuel mixing with oil, so looking at the fuel regulator & related thingy (plug in control box/circuit board) at the back wheel driver side area.
not dealing with some simple stuff here can turn into rich/raw fuel scenarios, driveability issues, blown cats etc

will update, so far, 3 front coil/plugs, that looked ok

was aware or became aware after purchase (130k 4yrs) of a faint ticking noise that could only be heard with the hood up. dunno if worse now but coming from the front bank, left side (from front), plug #4 area, will be checking it out cos understand that a loose cam cap bolt scenario can result in a miss ..or worse

lotsa good vids out there covers it all
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You seem to have covered a lot in your post, but left me wondering... did all the prior issues get fixed and if so, what was replaced/repaired?
If you have a random misfire, no codes, you likely feel the misfire when at low rpm. It is very difficult to feel a misfire at high rpm because it is so hidden. Given low rpm, is it a 'hard miss' that occurs steadily, can be noted in the exhaust sound, or is it an intermittent that more or less comes and goes? A hard miss would lead me to walking disconnect the injrector leads one at a time and check for cylinder drop/contribution. There may be a contribution test available in diagnostics that will chart the 6 on a graph so you can see which are not doing so well. A soft miss is harder to Dx.
Have you checked fuel pressure? Do you have a problem with high demand, such as hill climbs or accelerating hard?
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In the last 5 yrs, 2 prior miss instances with codes, plug coil scenarios resolved quick

The fuel scenarios (described above) have been going on 2 yrs, very randomly, acting up mostly rarely, getting a fuel pressure tester. Only figured out what all is likely going on there recently, from fully researching 'miss' scenarios

The very recent 'miss' development has been ~ 3 wks, is random & felt mostly at slower speeds. It's a misses a beat here & there deal, but mostly normal

The back 3 plug/coils were done at purchase, the front 3 were mostly unknown status, so all new parts there now, but the miss remains & old plugs looked ok.

Can't confirm yet, but the ticking noise described above, seemed to be gone, after that

As far as high demand goes, it may be playing out in overdrive & low rpms, then accelerating from there,, like a slight hesitation now.

Prob a more accurate description would be random occasional stumbles, noticeable musty at slower seeds, sometimes when idling but mostly runs clean

Dunno about the filter so fixin that
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The best way to find them random misfires with a scanner, is to enter mode 6. Then search for test #53. You will see cylinders 1-6, with real time misfires to the right in numbers from 0 to 200. 0 is no misfires, 200 dead cylinder.

View data while power braking. This data is the most accurate for misfires on Fords.
I have blue driver that i will look into
also looks like finding a capable scanner not a big deal
shows 70bux ca at

i found this vid very informative on the spark side

then these for fuel,

altho apparently on 04 & prior, the fp regulator/sensor is part of the fp
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Here's what bluedriver comes up with, looks to me that is all it does, as far as covering mode 6. Everything else in the report was a pass

looks like there is 1 fail (#4 of 6) for test 53, dunno if the fail for test 54 to 56 is relevant


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as far as test 53 goes, i see 6 entries with 1 fail (this image only shows 3 of the 6)

the 4th entry (of 6) shows fail, guessing that may mean cyl 4, which has a fresh coil & plug, the plug that came out looked good, and or the same as the other 2,

gonna run a tank with injector cleaner (dunno if ever done), dunno if relevant, but bluedriver is freeze frame capable


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You found the correct test area. Each scanner may show the test slightly different. But in the end, a fail is a fail. A number of failures, in a certain amount of time, will finally flag the check engine light. With the engine running, does your scanner show live data of the number of misfires as they happen?

The PCM uses the crankshaft position sensor, and checks rotational speed of the crankshaft. Every combustion event, the crankshaft speeds up. A misfire does not move the crankshaft as fast as a good combustion firing.

Mode 6 is the most accurate date of what the PCM "sees".

Rectangle Font Parallel Screenshot Number
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found this,
looks like BD only does short/long term fuel trim on 04

prob another piece of the puzzle is a random code p0430 that i've had thruout, & ignored, comes up 2-3 times a year

found these vids educational

So I just purchased a 2011 Ford Escape and it's doing all the things you're describing, is there a fix for this after all?
haven't sorted mine yet but suggest starting your own thread (usual forums protocol), where your specific situation, yr/model/engine/mlge/maintenance etc will be the focus, along with your specific info, that only you can provide, to help get right to it,

rather than get sidetracked by mine
Forgot that u could check for possible pending codes, which identified #5 cyl misfire, a new coil did the trick.

Thought the #53 test results were showing a fail for cyl #4, if u looked at it numerically, but that info applies to cyl #5, based on firing order, which i think
dwightbresemann was trying to point out to me, in this prior post #9

Also thought/assumed, i had ruled out plugs or coils as issues cos over time, had eventually changed them all out. So, turned out, it was a new aftermarket coil, that failed, after a few years.

Ended up trying out those coils on the front bank, due to easy access, cos they are the same as on my expedition (also easy access) & i had a bunch leftover

Went all new ford parts (plugs/coils) on the back bank, that doesn't have easy access ~ 5 years ago, to deal with a misfire there/then.
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