mrtoro

My 2005 cayenne turbo has 86k miles. There is a record at 62k For 8 coils replaced but no record of plugs.

It infrequently stumbles only at start up and goes away within seconds without ever triggering CEL.

Last week it was a more pronounced stumble and Cel. P0300,301,303,305,308.

I am going to replace plugs for sure. Should I spend another $240 and do coils again?

Thank you

Jonathan H

I wouldn't. Save that hard earned money. It would be easy to access in the future if necessary.

Petza914

Look for cracks in the backs of the coils and get a spray bottle with water in it. With the engine running, mist the coils and listen for any change in the way the engine is running. If there is, change the coils too.

JAGMAN1

Just do a thorough inspection of the coils upon removal. If no cracks, they are probably fine. If one or two are cracked, consider replacing just the damaged ones. If more than a few are cracked I'd replace them all.

It's not a hard job to pull plugs and coils, but not something you want to do twice within a few days of each other.

mrtoro

Thank you for your replies. I am planning on having two coils as back ups during this work. Any recommendations on plug brands?

Dan87951

If you are getting misfire codes it could be either plugs or coils. If it were me, I would do both. The coil packs for these cars have a history of not being able to last long regardless of version. I think Porsche is on version 12 or 13 now for coil packs? Honestly I lost count, however it isn't exactly confidence inspiring that with these many revisions Porsche still hasn't gotten it right!

FYI: Your Cayenne Turbo has a recommend spark plug change interval of every 40k miles too.

nrddct

If interested I have these used coils FS. Less than 40k on them. I replaced mine while doing the plugs. $100 shipped.

2009 Cayenne gts