Rough running engine - no codes

[Ahsai]

Actually based on your latest logs, I'm not sure it's a single cylinder issue anymore (there were misfires on cyl 2 & 3) so I doubt a leak down test will reveal anything. May want to just drive it with the MAF unplugged for 1/2hr or so. The performance will be reduced but at least you can feel if it helps the rough idling.

 

Your cam deviations look excellent so I doubt IMS and cam padding are the issues. BTW, the AOS on your car (MkII) uses a rubber hose and not a bellow.

[Octane4evr]

Drove with the MAF unplugged all the way home ~45 minutes. No noticeable difference in idle after the drive. 

 

The comment from Porschetech3 on the crankcase vacuum being too low has me wondering about the seals you mentioned or anything else that would cause reduced vacuum in the crankcase. Other than the seals you mentioned, should I check anything else when I have it on the lift for the oil change?

 

Also, my independent Porsche shop expressed a concern about lifters sticking causing this issue. Any thoughts on that?

[Ahsai]

Good. I think it's not related to the MAF sensor then.

 

It would be nice if the shop can perform a smoke test to check for intake air leak and crankcase air leak.

 

Sticky lifter(s) are entirely possible but so are sticky injector(s).

[Octane4evr]

If the seals for the crankcase are leaking would I see oil leaks? This engine uses almost no oil, about one quart per 6000 miles.

 

 

Edited November 17, 2017 by Octane4evr
Correction

[Ahsai]

4 minutes ago, Octane4evr said:

If the seals for the crankcase are leaking would I see oil leaks? This engine uses almost no oil, less than one quart per 6000 miles.

 

 

I would think so.