I use the product from OBDLink and the android app ‘Torque’ (paid version).
I think I got it more than 10 years ago and since then, so many products and software developed that you now have all sorts of options.

Even with that ancient product, I was able to diagnose intermittent O2 sensor issue (voltage shifted from time to time) so the latest ones should have faster sampling rate and better interface.

If your phenomenon is specific to certain VSS, then I agree, not misfire related.

The fuel pump stays in low speed mode at such low load region.

A/C signal is mainly for the idle control module so once outside of it, you should only notice the A/C CL On/Off and not the rpm change.

In order for the VSS to drop for 1 – 2 sec, should be something related to multiple or all six cyl so IG Timing, EGR, etc would be interesting to monitor.

Any aftermarket modifications?


Kaz