Hi,
The idea behind a Vtec engine is to change valve timing and valve lift based on demand and RPM. In this case, you have an engine designed for computer-initiated change that doesn't happen at the higher RPM operations. The Vtec is designed to create a smoother running and higher-performing engine. At higher engine speeds, the cam profile allows greater valve lift, which allows more air into the cylinder. Thus, the engine is able to create more horsepower
Based on different inputs, the ECU is programmed to switch from the low lift to the high lift cam lobes under specific conditions. And yes, oil pressure plays a role in this as well. However, in your case, the ECU isn't able to do that which is causing the higher RPM issues.
Let me know if that helps or if you have other questions.
Take care,
Joe
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Sunday, March 13th, 2022 AT 6:31 PM