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Discussion Starter · #1 ·
17ST1 16K Miles. mods are listed at the end of the post.

So one morning on the way to work (it was literally 0 Degrees F) I started experiencing low speed misfires. I let the car do its warm up before driving it, and also when its this cold i never go into boost until im atleast at 165-170 on my oil temp. So on this trip i didn't even make it to that oil temp (around 150ish) so i didnt get into boost at all, turning into the paring lot in second around 10 mph im getting hesitation. Driving to the parking spot its fine. Get into first, start letting off the clutch to pull into a spot, more jerks and hesitation, multiple and rapid. No CEL.

After work I decided to get deeper into it. Let the car completely warm up at idle, no weird starting or idling. A couple misfires cause of the cold but its normal for this car since i bought it at 2 on the odo. Got to around 165 on my oil temp. started pulling out of the spot. stuttering, hesitation, jerking, speed gets to 5-10 mph and all is well, no cel or anything.

These are clear as day misfires, not a rooky who cant work the clutch. Driving at speed is totally fine, except when depressing the clutch and blipping the throttle to rev match on a down shift. A misfire can clearly be heard on the low end of the blip, i typically blip the throttle at 35% for revmatching. This happens every. time.

Cars totally warmed up, been driving for 50 miles now, and i can replicate it everytime. Switch monitors on AP, Misfire count confirms every misfire i hear and feal. Im thinking bad gas now, No Negative corrections on the cylinders 1&4 but OAR is at -.50, Bingo! "I just filled up, its cold, its probably winter blend and the tune not liking each other" Run out the tank, symptoms persist throughout.

At 20m to Empty, go to Shell fill up with 93, re-tune the car to Cobb OTS stage 3 93 OCT thinking the stratified might be a little too aggressive for the temp, weather, and gas. Reset KAM, pulled plugs and swapped them for the stocks i removed earlier in the year.

This helped a lot. The misfire is still there at times though...i have new NGK IX and 4 coil packs on the way. here are the ones (Plugs) i pulled out below. I cant see anything wrong. Can anyone else see something im not?

Screenshot_20171229-161008.jpg

Does anyone have specific instructions for a datalog i can run? What monitors should I log?

Any ideas would be helpful. Ive found at least 4 other members in the past on this forum with the same exact symptoms, but they never updated us as to whether or not they got the problem fixed.

as far as i can tell...this is not recall related, nor wire harness TSB, or the dreaded chronic cold start misfire issue that ford still hasn't resolved. those symptoms dont seem to match mine consistantly.


Cobb CAI
Cobb CB exhaust
Cobb Catted down pipe
Cobb Shift Plate
Cobb Access port
Cobb FMIC
Cobb knob
Cobb Rear motor Mount
Boomba Symposer delete
Boomba Oil Catch can (PCV)
NGK Iridium IX 6510 1 Step Colder Spark Plugs
Stratified Automotive Flash Tune (93 Octane)
CP-e Exhale kit (Tial)
 

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1. Turbos do not like temps that low, I dont recommend beating the hell out of it.
2. It sounds like, and I forget the eactly name but its basically putying a load on thr car when you are at low rpms. Mazda has this issue and engines blow with them, due to thr direct injected engines.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 

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Discussion Starter · #3 ·
1. Turbos do not like temps that low, I dont recommend beating the hell out of it.
2. It sounds like, and I forget the eactly name but its basically putying a load on thr car when you are at low rpms. Mazda has this issue and engines blow with them, due to thr direct injected engines.

Sent from my SAMSUNG-SM-G930A using Tapatalk
LSPI? (low speed pre-ignition) if thats what you mean, I really dont believe thats the cause. Yeah i definitely don't beat on it at these temperatures. I'm very careful lol

Im going to switch plugs and coils on tues the 2nd. if i cant fix it with that my next step is going to be fuel injectors, then if not those, the HP fuel pump.
 

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Discussion Starter · #4 ·
The coils came early, going to switch the plugs to new NGK iridium IX and all four coils, with a compression test prior today. Just warmed her up at idle until i got to 160 oil temp, did some cruising and couldn't pull any negative corrections on any cylinder, did two WOT pulls, both flawless. Still no smoke, or CEL, Misfire remains :(
 

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Discussion Starter · #5 ·
I checked compression. 170 across all cylinders.

Replaced all 4 coil packs and plugs with new. (Old plugs looked great)

Still have misfire, anyone have any ideas on what I should try next?
 

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Discussion Starter · #6 ·
Can shaft positioning sensor ordered. Checked oil level, good level. Still have misfire.
 

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I noticed you have the Stratified flash tune. It may be best to post this on their thread and see what kind of response they give. I can't help out much more than that.
 

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Discussion Starter · #8 ·
Took the ST to work instead of the company F350 yesterday. Had work in Manhattan. Over the last few days ive noticed a decrease in misfires when the ambient temp is higher, it never completely goes away though. Driven the car for HOURS in all kinds of conditions just to try and diagnose this thing, have had the oil temp up to 185 on these absolutely freezing days and the car remained the same even though it was definitely at operating temp.

So yesterday, after slugging it out to get into Manhattan I get to my destination and park the car on the side of the street and just let it idle while I sit and wait for my co-worker. He wont be there for another hour, so i turn on the heat and pull up good ole Netflix.

I happen to glance at the AP and my Intake temps are frozen, right around 30-33 Degrees cars been idling for 45 minutes now and i have an open air box, normally my intake temps would be near 100 degrees just sitting here like this idling. Now im interested in why TF this is happening. So I get out of the car for a couple minutes to see if i can feel a breeze or anything that might be pushing out my heat through the big mouth or the fact that i dont have the grill shutters any more. Nothing, didn't even wiggle my nose hairs.

Get back in the car, intake temps, charge temps not really budging. Charge temps are fluctuating more, +/- 10 degrees, but not the intake temps. Then all of the sudden, intake temps climb RAPIDLY, they approach 90 degrees in the span of 15 seconds from 30 degrees. it holds there for a while. Im looking at the idle, it hasn't budged. Then as suddenly as it went up, it starts going down at the same pace. I JUMP out of the car....it has to be a breeze....Nothing. Absolutley nothing. No breeze, no idle change, nothing.

So i sit there and watch this happen 3 more times without any idea as to whats causing it. On the way home, misfire is still there, and still felt. I can reproduce it with every rev-matching down shift. I can reproduce it taking off in first gear. its still the same.

Woke up today, went out to start the ST and said **** it im going to let it idle for like a hour before i leave, this is the warmest day weve had since this started happening, hoping engine heat and the warmer air will thaw out whatevers F'ing my car up. So I made breakfast and checked e-mails. Then headed out. Get to the car first thing i look at is intake temps....now reading accurately! Im at like 105 which is about right, charge temps not far behind. Stare at it for 5 minutes. Not fluctuating at all, they are climbing as expected but nothing like yesterday with the dramatic temp climbs and drops. Check the misfire counter....wayyyy lower than the past week.

So I start smiling in my mind "I think it might be gone!" start pulling out....no misfire, get down the street...smooth as my wifes ass. Get on the highway, drop down a few gears. Nothing no misfire. I decided im going to stay light on the throttle and stay on the highway as long as possible, to blow all this heat out of the engine bay. I'm trying to freeze this ***** again to see if it will come back. Sure enough. It starts F'n up again, and where im at now is almost 10 degrees cooler than where I was.

I get to where im going, and let the car idle while i go do my thing....start driving away and poof misfire is magically gone now and the ambient temp has climbed to its high for the day. A whopping 31 degrees. Drove the car the rest of the day (about 2 more hours and 60 miles) not one misfire.

So my conclusion is this car just doesn't like the cold. Or i have a bad map sensor on my intake right after the filter.
 

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I definitely agree. My 2015 doesn't like the cold. In these frigid conditions everything seems sluggish and frozen until it gets some heat in it. I have gotten into the habit of not idling the car to warm it up in the morning. I simply start it up and let it idle for 1 minute before pulling out of my driveway. I drive it conservatively until I hit 120F oil temp.

Being completely honest though, this week with temps hovering around 0F I have let it warm up about 10 minutes prior to jumping in simply so my balls don't freeze off.
 
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