Not at all, the ECU memory can be checked using a multimeter, I'm not sure on the logic behind when a code is stored or not, but I would think if you switch the engine off when it appears it will be retrievable.


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Even if you can't get a code, there's only 13 things that can cause a code. Half of them can be improved by cleaning the sensor (and you may as well check it's working while you have it out, most of its in your workshop manual)

When it goes away when you punch the gas, that's exactly what my Ute does, suggest cleaning air flow sensor and manifold pressure sensor to start with