Check engine light came on first week September. However car still drove normally. Fault code showed fuel pump misbehaving and was replaced.

Then mid-September car would put its nose down and act fuel starved. Getting up our numerous hills would slow car to about 30mph.

Restart and all was well. Then without warning problem reoccured.

Dealer could find no fault codes.

Two days later, while driving suddenly all orange warning lights came on as well as the red parking brake warning. This was erratic but generally happening within two miles of a restart.

Dealer ran fault code on each warning light and determined that a vacuum issue was the common thread.

There is a device under the rear seat which handles the vacuum. It was evidently not torqued correctly at factory and had worked its way out enough to cause loss of vacuum.

Merely tightening the bolts cured the problem!

This is my fourth Sonata and the only one that that has any issue above a brake light in my 2013.