Engine missing and Tacho intermittent
 

Accent 2003 manual LC 1.6L.
Two problems that may be related-
(1) The engine misses intermittently while accelerating only, noticed mainly in the 2K-3K RPM range. It's not exactly the same as the missing from a faulty ignition coil. More like laboring but irregular.
(2) The Tacho either (a) works for the whole trip or (b) doesn't work for the whole trip, or (c) (rare) show 0rpm on idle then increases during driving.
I have seen a youtube video on a newer model Hyundai where the tacho was intermittent like (a) and (b) above which was fixed by replacing the crank position sensor. I'm amazed the engine can even run with that faulty.
Where do I start looking?
Whats the most likely suspects?