29D0 Cylinder 4 Misfire -Only when idling, ESPECIALLY in Park position.

[matreyia]

e85 @ 80% Flex Fuel
e85@ 40% Flex Fuel - doesn't matter what percentage.
Port Injection
DCI
DP
PR Coils
Upgraded vacuum hoses
Just replaced boost solenoids

Last night replace boost solenoids and test drove. silky smooth powerful response in all speeds and gears.

This morning, very foggy, humid morning...started the car and it misfired on #4 with code 29D0.
Misfire goes away if car is in gear. Misfire returns at stop light but not nearly as much as when the car is in Parked position.

Added techron fuel system cleaner, drove around for a bit, no change. Plugs are last Thanksgiving installed. PR Coils last xmas installed. I can hear a faint high frequency sound on driver side engine bay but cannot locate. it is BARELY audible, but definitely there. You would not hear it if you were not paying attention. like a super high pitched whisper level hissing. almost ultrasonic frequency.

WOT is smooth and powerful. Driving in gear also good... But in 'park' shifter position...misfire on #4. And at stop lights, same misfire, but only 5% of the amount as in 'park' position. Sometimes SES light comes on, and sometimes not.

I thought maybe the humidity and fog...but it's noon now...still same. Will check plugs when I get home and update. Any ideas are welcomed.

 

[matreyia]

Ok, so... I posted some reviews about my BMS testing of their BOV adapter kit amd how it caused detonation and backfires vs. The Vader Solutions kit. Seriously loud explosions and had to pull over.

Well it appears that those detonations cracked cylinder 4 spark plug. And that was the cause of the rough idle and misfire whenever the car was not in gear. See photo.