Coyote Gen3 rough idle at start then smooth

[toadster]

3+ months later, still no progress... can't get Ford to call me back (grrrr) - won't reply to emails either...

who can I escalate this to?

[Railroad]

With nothing to lose, you might consider throwing this problem out to some outside sites.
I would consider this site, you can refer back to you thread here.
https://svtperformance.com/
IMO this has to be harness or ECU. I would think Ford would cover your cost, after you buy the second of either.
Ford did send out a second harness to a builder here in my state, curing the problem.
Good luck,

[toadster]

agreed, what we're trying to determine is which harness... We had quite a test requested from Ford, the only test that 'failed' was JF8 Check the Suspect Coil Driver Circuit for a Short to Ground

https://docs.google.com/spreadsheets...it?usp=sharing

all 8 coils showed O.L. on two different multimeters with this test, which may suggest a common ground break, but not sure if it's the PCM harness or the actual harness on the engine, will be trying Ford again today

[toadster]

finally got a hold of Ford, they're thinking it's the engine harness... will reach back out tomorrow, hopefully with a harness in shipping!

[Rsnake]

Idle and startup issues resolved and might be informative to other Coyote users.
I jumped into this thread a while ago and thanks to snowman on the forum he has both issues resolved.
The high idle issue is a Ford programming error as the pathway in the idle torque value needs to be -41 and ford has it set to 41. Snowman assumes it's a error in part on the person who copied the Ford Mustang tune to the crate motor tune and missed the negative. Once changed to -41 it idles at 700 and stays at 700 instead of jumping to 850+ after a few seconds.
My second issue was the running rough for 10-15 seconds on startup. After Snowman looked at some data logs he realized I had the O2 sensors reversed. Once I changed them that issue is resolved as well. I drove 75 miles today and it runs perfect. Cannot believe I lived with this for two years.. I will put up a video with details on my YouTube channel. Cobra Daytona Build in the next week.