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spike021/Josh told me about the problem he's been having with his car where it feels like it's going to stall (with a quick flash of a CEL sometimes) after clutching in when coming to a stop sign/light. His datalog indicated that the port injection system is biasing a bit lean and that the injection is coming back online on deceleration a little late versus how it should be.
Today he messaged me and mentioned that he was at a tire shop and that they informed him that he had nails in both of his passenger side tires. Ah ha! I immediately knew what was going on with his car.
The rapid rotation of the metal in the two nails were disrupting the EM field and the ability of the TPMS sensors to reliably communicate with the ECU. As a result, a high amount of erroneous data was being received which meant the ECU had to increase it's use of error correction. This lead to it's internal CPU's timing subsystem being delayed. The delayed timing meant that the port injector idle fuel mapping is slightly slow to engage.
Boom, removed the nails from the tires and problem solved.