CEL with some flashing

[JFP in PA]

Originally Posted by Fhelfrich

I have the CEL on, with rough slow idle (600 rpm or so). If I sit at idle for about 30 secs the CEL goes from solid to flashing, slight throttle increase takes it back to solid.

Background - 2000 Boxster S with 78K. Recently took it to a track day, with a known weak AOS, only blew smoke a couple of times while driving in the prev 6 months and would occasionally blow some on start up after a spirited driving session. At the track I had several incidents of fogging for mosquitoes at speed, especially after the real hard left-hander. Instructor was experienced Porsche driver and said not to worry but fix the AOS. CEL came on late in the session and has been with me since (couple of hundred miles). Instructor didn't seem to concerned about CEL as it was most likely related to AOS.

On the way home from the track I noticed rough, slow idle and that has been persistent.

Have since had AOS replaced. CEL came back on about 2 miles later. I kind of expected that mechanic would clean MAF, but it sounds like he didn't.

Will stop at Autozone this PM to see if they can pull codes.

So, I have CEL, rough idle but it runs great other than that. You now know all that I know. Suggestions?

First of all, any time one of these engines starts spewing smoke is a time to stop and be very concerned.

There should be no reason to clean the MAF, oil from the AOS system enters the intake behind the throttle body and way past the MAF. You may, however , have a lot of oil inside the intake runners. You may have also oiled down your O2 sensors and the cats as well.

Get the codes read, preferably with a Porsche specific system (Durametric, PIWIS, PST II).