HELP! Idle Consistently Fluctuating and Causing Hesitation 2016 GT Supercharged

[nahmed405]

Sounds like its time for a compression test.

Lol the dreaded test I didnt want to do was done. These are the results:

195, 210, 210, 210, 195 190, 200, 180.

Cylinder 8 was the last one with 180psi and that might be the culprit. But I did a leak down test right after and it sounded the exact same as when I did it from a good cylinder.

Here is the good cylinder results
Here is cylinder 8 results


I was reading the forums that CrackedHorn sent and the thing that I think is closely related to my issue is a cam phaser. I had this on my list to check out but I am hesitant since it is a pricy fix and the way people describe their symptoms, it doesnt exactly match mine idle issue since it happens all the time with slight fluctuation, not randomly and abruptly.

Crankshaft position senor is also something I will look into after reading the forums but what do you all think about these numbers for compression. I was reading another post about it and couldn't get a definitive answer if this was normal.

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[CrackedHorn]

Total shot in the dark here but did you try a KAM relearn and crank relearn?

Admittedly I'm just throwing spaghetti at the wall, but there shouldn't be any harm in doing so.

If your fuel trims look good and you aren't finding a vacuum leak, it's worth a shot.

Compression numbers should generally be within ~10% of eachother from what I've always been told. The number itself doesnt matter too much unless it's really low as all gauges read differently. My compression was 212 on all cylinders except with #5 being 240, for instance. No idea why. Probably carbon.

Someone on the forum told me that the Ford workshop manual says within 25% of the lowest and highest Is acceptable. Which sounds awful high to me, but I'm no expert, either.

By both metrics, your compression seems to basically be within range as far as I can tell.

 

[nahmed405]

Total shot in the dark here but did you try a KAM relearn and crank relearn?

Admittedly I'm just throwing spaghetti at the wall, but there shouldn't be any harm in doing so.

If your fuel trims look good and you aren't finding a vacuum leak, it's worth a shot.

Compression numbers should generally be within ~10% of eachother from what I've always been told. The number itself doesnt matter too much unless it's really low as all gauges read differently. My compression was 212 on all cylinders except with #5 being 240, for instance. No idea why. Probably carbon.

Someone on the forum told me that the Ford workshop manual says within 25% of the lowest and highest Is acceptable. Which sounds awful high to me, but I'm no expert, either.

By both metrics, your compression seems to basically be within range as far as I can tell.

Phew! Was really stressing the compression numbers since I did it.

I did both the KAM relearn and crank relearn. No result.

On my list of parts to throw at this is:

1. Fuel injectors /cleaning
2. Crank position sensor
3. Camshaft position sensor
4. Cam phaser

I'll be all out of things to try after that lol. I'll do this soon hopefully.

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