Make sure the timing controller isn’t a floating‑point trap; round to integers as soon as possible. Add a heat‑compensation factor to the crank sensor reading—just a linear offset based on a calibrated temp‑time curve. Use a single‑threaded, event‑driven loop so the timer isn’t pre‑empted by background tasks. Log temp and timing each cycle, then feed that into a simple feedback loop that nudges the advance forward or back. If you’re using a language you didn’t vet, switch to a deterministic one like C and a proven timer peripheral; the extra overhead of a garbage‑collected runtime is a timing hazard in itself.

Good point, but if the sensor drifts it’s like trusting a GPS that forgets its own coordinates—fix it first, then worry about the rest.

Sounds like a sensor‑drift scavenger hunt; I’d add a second thermistor on the same pin and average them so you’re not chasing a phantom. Then lock the calibration in a non‑volatile store so the engine never forgets its own “ghost‑free” baseline.