High long term fuel trims at idle 2018 Mustang GT, Gen 5 Whipple Stage 2 with Kooks

Hey guys, I seem to experiencing high LTFT on my 2018 mustang gt with gen 5 whipple stage 2 with kooks headers and high flow cats, Nguage and VCM scanner is reporting the long term trims are +20 at idle so running lean, car is running just fine under load and trims close in close to zero but they dont look great, not sure whats causing the lean condition, cant find any vac leaks or exhaust leaks so wondering its the tune. Any advice would be great. Attachment 101902

post Log

Injectors that came with the kit?

Whipple Cal?

You need to smoke test your system

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Originally Posted by ozzieuk

Hey guys, I seem to experiencing high LTFT on my 2018 mustang gt with gen 5 whipple stage 2 with kooks headers and high flow cats, Nguage and VCM scanner is reporting the long term trims are +20 at idle so running lean, car is running just fine under load and trims close in close to zero but they dont look great, not sure whats causing the lean condition, cant find any vac leaks or exhaust leaks so wondering its the tune. Any advice would be great. Attachment 101902

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I had this same issue on same setup minus headers... Ended up being MAF period was pretty far off at idle.

If you sit a lot at idle and IATs get high compared to other parts of the curve there will be a decent difference on the idle cell. Could be dialed in better though +20 is a bit high.