HansStuck

Hi folks,

2006 Cayenne S w. 108k miles.....running fine, except it developed a leak from the passenger side valve cover.

Yesterday I spent most of the day replacing that side's gasket, spark plug gasket, and camshaft adjuster seal. I also replaced the plugs on both cylinder banks, as well as the air filters (probably useless data, but just making sure I don't miss anything obvious).

I did not change the coil packs, as they are relatively new (05 part number packs) and were doing fine before the gasket change.

So, I get it all put back together, and.....rough start, lumpy idle, rich exhaust smell, and a P300 (multiple misfire) code, as well as misfires on cyls 2,3,4,5,6, and 8 (no codes on 1 and 7).

I'm about to go troubleshoot. I believe it to be a vacuum leak somewhere, since I didn't change the gasket on the 5-8 bank, but I'm still throwing codes on that side. Also, there's no oil coming from the gasket I did change, so the seal seems to be good all around. Surely I didn't have 6/8 coil packs go bad in a matter of 12 hours did I?

I'm a bit stumped....just looking for some possible directions to hone in on as I try to solve this one.

Thanks in advance for any suggestions.

HansStuck

So just for fun, I swapped coil packs 6 and 7 in an attempt to rule out the packs, reset the codes and.......proceeded to take the car out around the block running as smoothly as it has in the 2 years I've owned it, and no codes in 10 minutes of driving.

This is almost too good to be true. When I removed and replaced the valve cover did I just introduce a large amount of air to the system that caused the misfires when I first started it???

I don't want to look a gift horse in the mouth, but any other reason for this behaviour any one else can think of?

wrinkledpants

Anytime I tap into the intake system, I end up with a rough start that works itself out after 5 minutes of idling. No misfires are registered, but it is misfiring. I really don't have an explanation for it, especially since no electrical connectors have been removed. It even did it when I changed the o-ring on the in charge pipe, and nothing else. Starts fine, runs rough, smooths out over 5 minutes or so.

HansStuck

Thanks wrinkledpants, that's confirmation enough for me.

Whew...I just got my Sunday back....really expected to have to redo the whole freaking job today!