North American Motoring - 2011 rough idle

North American Motoring (https://www.northamericanmotoring.com/forums/)

- Stock Problems/Issues (https://www.northamericanmotoring.com/forums/stock-problems-issues-188/)

- - 2011 rough idle (https://www.northamericanmotoring.com/forums/stock-problems-issues/331638-2011-rough-idle.html)

Hello everyone,

I just bought a 2011 MCS with the JW tune that has 77k miles. I have had the car for about 2 weeks, everything has been running smoothly and all of a sudden the check engine light came on yesterday and the idle started bouncing between .5 and about 1.2. I did the check list and the low fuel warning was shown, although I have about a 1/4 of a tank of gas left. I am guessing the cause may be the HPFP, but hoping not since as new one was installed 4k miles ago. I have ordered a ODB-II scanner which will be here tomorrow. Any words of wisdom offered would be awesome.

Thank you

Rough idle is usually going to be either fuel or spark. If you scan the codes and get a multiple cylinder misfire and/or low fuel rail pressure codes, probably HPFP. Otherwise single isolated cylinder misfire is probably a bad spark plug or coil pack.

Thank you for responding. I got the code, looked under the hood and noticed the air intake hose was cracked and disconnected at the turbo, the turbo the dealership installed about 8. I followed the intake up to the filter to find the filter box was only attached with the one screw and the other rubber grommets were missing. Anyway, I ripped everything out and I am searching for a new air intake setup.