This is a discussion on Stuttering Idle and Misfires on light throttle - Am I in trouble? within the Focus RS TroubleShooting forums, part of the Focus RS Garage category; Hi all, VIDEO: https://drive.google.com/open?id=1VG...bBRSLWlvZ7PU1m Sorry to be another worrying newbie but would really like some thoughts on the sound my car is making. MY RS ...
Sorry to be another worrying newbie but would really like some thoughts on the sound my car is making.
MY RS is 2016 year and had the HG recall completed about 4-5k ago.
Adam Tune+ 98 Tune w/ Cobb
Scorpion cat back exhaust
Sorption downpipe (sports cat)
GFB DV+ T9360 diverter valve
Airtec Intercooler piping
Mountune Rear Engine Mount
Radium catch cans and baffle plate
NGK LTR7IX-11 (6510) 1-step colder Spark Plugs - Pre-gapped to TUNE+ Spec
Mountune sound suppressor
The video is of the car about 2 minutes after a cold start. I noticed this the last time I drove it and only started this time to record.
If I lightly put my foot on the accelerator in neutral, the car will stutter faster and also record misfires. It appears to rev higher fine.
The coolant level is fine and there is no white smoke, the video was taken at 9 degrees Celsius outside so there may have been a bit of moisture.
Cobb has not thrown any error codes, no CEL on the dash.
Any thoughts on what this might be? And what my next step should be?
I am worrying it might be signs of the end...
The first time it happened, I started the car up and drove out my driveway, for about 5 minutes the car was misfiring pretty badly on acceleration and then calmed down.
Not sure if that helps.
I have taken it to my mechanic and they took out my one step colder spark plugs and replaced with stock.
The issue is still there but less apparent.
They think it is either a custom tune issue or injecter no4 is not spraying correctly and needs to be replaced as it looked a bit black.
It is at its worst on cold start and light acceleration but gets better after it warms up.
Anyone heard any stories of injector issues?
Check your air intake for any leaks.
Now after watching video, that to me sounds like big end bearing noise.
I wish you luck with the repairs.
2016 FOCUS RS
Forged 19" Cup 2's
HG Rev C 11.10.18
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This is the idle sound after they changed the plugs.
They also performed a compression test and returned 125,125,115,118.
Still think it could be bearings?
Why has no-one suggested returning the tune to stock and checking idle then.
If the issue goes away, its the tune.
If the issue remains, its not the tune and more than likely is something mechanical.
You haven't done any modifications yet that would preclude you from running a stock tune safely.
Mis-Fires are almost always related to fueling, timing, or damage in the cylinder.
A failing bottom end (rod knock) doesn't show up as a mis-fire. The death rattle is instantly recognizable. This is rod knock without the soon to be present squeal.
And this is a rod knock with squeak.
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OP, there were a few stories of injector damage from the HG repair. Are you getting misfires on one cylinder or random? If on one cylinder only, and you're mechanically inclined, consider swapping the injector. IIRC they're cheap enough that it might be worth your time.
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