runs rough at times on start up
 

at times on cold start, the 911 will run rough and is low on power for a few miles then abruptly it clears out and runs great. it feels like its on on 7 cylinders then you flip a switch and its fine. it happens off and on but mainly if the car sat for a week or so without being driven. i have my thoughts but any ideas?

What year is it?

I'd be happy if mine felt like it was running on 7 cylinders. ;)


Seriously though,... mine does the same thing. I envision oil fouled plug. Takes a bit to clean off and start firing.

Could be worse. A friend had an Audi that sounded like it was running on five cylinders :eek:

Could also be a low battery not supplying enough power to the Motronic system. Is it Motronic? If so, charge the battery before you give it another cold start & see if that makes a difference.

Hey Cellison, i think i've got my issue figured out, and this may apply to yours as well.

I decided to pull a couple plugs just to check their condition (car is new to me) one plug out led to a compression test. Which then led to another plug, and so on.... Got to cyl. #6 and the plug is oil fouled big time !

Take a look at your plugs and see what story they tell.

JLEX I think the battery is charged good but i'll look at it closer.

TORI, the plugs have been in for a while so i'll pull them to look at the condition. what was your compression especially on #6?

#6 was 150 (this is still good compression, but low compared to the others)
#1-#5 - 172-188

If you need help with changing out/checking your spark plugs be sure to check out our article here: Porsche 911 Spark Plug Replacement | Pelican Parts DIY Maintenance Article. Good luck and hope you figure out your issue soon.

Yep, i used that one last nite. Thanks. This site is such a great resource.