just adding another issue/repair for the board here.

A while back my Elantra had a change in its idling and performance.
Became sluggish and coughing.

I went to Auto Zone and did the Free Code Check and it showed to be a vacuum error, I can't recall the code #.

the solution was to spray a little carb cleaner ($2) around the vacuum lines and as this cleaner gets sucked in a leak or hole in a hose, the motor "coughs", becomes sluggish.

This method worked well and took about 3 minutes.

The hose going to the Fuel Injection had a huge hole in it.

Replaced the small hose for about $2.


Matter of fact I suspect this hole was there when I bought the used car and had gotten worse. Because not only did the car run much better after replacing this small hose, Gas mileage has been a huge improvement too.

The mechanic/AutoZone employee told me this air line supplies air and the fuel is adjusted to maintain a correct mixture/ratio. So with the air being sucked in through the hole more gasoline was being entered in, to keep the ratio/mixture correct.

Less air= less gasoline needed

He sounded logical, and my gas consumption has improved dramatically, so I will side he is right.

hope this helps somebody...

 

Sound like PCV hose collapsed and rip/hole-vac leak.. goes from plenum chamber to fitting attached to valve cover..

Go and lightly spray along the seam where intake mates with cylinder head, intake gasket likes to crack at cylinder 2 & 3 and give code if condition bad enough.