If you want accurate numbers you need to use an accurate transducer. I had a car here 2 months ago that the owner complained detonated and ran terribly at wot. He thought he was at 16psi manifold pressure. When I used a calibrated transducer and measured he was over 20psi from about the second he throttle hit 50%. His gauge was incorrect. Not even close. Map sensors can have error, leakage in the circuit if other items are teed in and leak, the sensor itself can leak especially if it’s a plastic GM style.
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