My 2011 Accent stalls and will not restart right away, but starts after a few minutes. Diagnostic says ignition is OK, replaced fuel pump, new spark plugs and replaced one ignition coil. The last time it stalled, the tach did not work after restarting. Tach worked fine the next day. Any ideas? Thanks.

 

Hate the mechanic which chooses to throw parts at a problem without finding out what is really wrong.
I know it isn't easy to find intermittent problems. Tach not working and then started working sounds like a reference voltage is missing.
Happens with a shorted wire. Tach is a crank sensor or cam sensor.
Look at the engine bay and look especially for wires that are rubbing or next to metal.
Exhaust pipes. Actually looking for frayed or worn insulation that could short out.
The cooling of the engine could move the metal or wires out of the position which causes the short. It isn't easy to find.

 

I think you have a faulty ECU. Go have it checked.