Hardly. My problem was caused by the inlet manifold wiring harness being incompatible with the main loom. I put the original 1AFA harness back on and the problem completely disappeared.

It would appear that there may be a couple of pins swapped between OFAC and 1AFA looms on this harness but I haven't had a chance to find out which wires yet.

In any case the affected component appears to be the ECT sensor and if you unplug it the idle and general running improves considerably. Once I've tested the two harness I'll find what the difference is ...