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Engine Miss at anything over 20psi


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Chasing an annoying problem. Run down on the car is Crow Springs, Bigger Front Mount, Turbosmart Actuator 12psi spring, high flowed turbo, new plugs and NGK coils on E85 - have tried anywhere from 15-19 degrees doesn’t really change and lambda .75-.85. As soon as it hits 20psi engine gets a miss that clears. Plug gap went from .7-.6 now at .55 still the same. Any advice?  I have also noticed that my actual timing isn’t what I’m commanding - it’s pulling timing and logging all the spark parameters and doesn’t show where it’s getting pulled from? 

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Put new OEM coils back in.

Also confirm that you aren't getting valve float. Does it only occur at peak torque? Do you have a lumpy idle after a dyno run? What happens if you run spring pressure instead?

Timing is probably due to the various adders. You can log individual cylinder spark and see if knock retard is kicking in.

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The coils are straight from Ford. I’m leaning towards valve float, but I can’t see it being an issue as there fairly new crow springs, but that’s where everything is pointing. No lumpy idle after a pull, knock sensors are disabled with e85, I run Tune 2 at 15-16psi and no issues. 

Interesting thing is I pulled it off the dyno and it’s clearly been spinning the tires. I will road test it to see but I’m wondering if it the tire loading and unloading on the roller as it comes onto boost that’s giving me that jolting miss I’m feeling. 🤔

Edited by JMSMotorsport
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