__ Charley __

Hi!
No carbon deposit or visible trouble.
It appear to be a faulty part.
The throttle boddy was in stock at the warehouse (in good quantity) it also is a good indication that it is a common problem. The tech tested it and compared it with another 911 in the shop. The graphic was truly different. Before the change my car stumble.. Something at low idle had a 'lack' and rough idle +-150 rpm.. Since the change never happen again..!
My car has 100k kilometres.

drdantheman1

Did you have a check engine light at all? Any codes?

__ Charley __

No code or check engine!
​​I had to change my variocam solenoid and valve lift solenoid Who made some code but i highly suspect that it was related to the faulty TB.
If i had to make it again, i will change the TB first..
But with the symptoms of rough idle and hesitation stumble.. No code ever.. Once TB change guys it is a New car!

Joec500

especially if you have basic tools and comfortable removing your bumper you can DIY super easy in about 1-2 hours.

I bought the generic Bosche part from Autozone for about $150 with some coupons and used my PIWIS 2 to calibrate.

__ Charley __

Good point
The tech to calibrate did a fuel trim reset.. Maybe important to know..

koala

Throttle body didn't solve my stumble, so I've got new variocam solenoids sitting on my workbench waiting for some warmer weather. Really hoping that makes the difference.

Glad that the throttle body solved your issues!

rnl

Variocam solenoids wear out on these cars. Porsche, unlike BMW, ignored this fact. Seems to me that by not including these items in routine maintenance, the projected cost of maintenance was distorted by Porsche. BMW recommends replacement of a similar device at 75k.

Ducaiti999

Ok. I'm leaning toward my cam timing also. I've read several different things about cam solenoids. Its my understanding that there is a timing solenoid and a lift solenoid. When you say Variicam which one do you mean? Does this R&R require the cams to be locked with a special tool, or just unbolt and replace?

Porsche_nuts

That is disappointing news . . .

koala

I'm ignorant to how many solenoids there are and what their specific function is. All I know is that I have two new ones ready to install and these are in the same location as the spark plugs. I'm not sure if there are others as well!

These are just a direct part swap, and I assume they won't need anything too unusual as far as tools go, but I'll update here once I give it a try.

Ducaiti999

Thanks. What car is this on? What is the part number for the solenoids in question?

Thanks again

koala

This is on a 991.1 S - the parts are 2x 9A1-105-308-03 Engine Variable Valve Timing (Vvt) Solenoid

I ordered mine from Get Porsche Parts - cheaper than here in Canada even with shipping/duty.

koala

Changed my solenoids today. The passenger one was a PITA - took me about 2 hours. Driver side took about 30 minutes.

TL;DR - car drove perfectly. I could not recreate the stumble.

To be fair, now that I've done it I could do both sides faster. Part of the passenger side difficulty was also figuring out how to remove the electrical connector, and I made the mistake of not removing the connector until after I had the solenoid unbolted.

Lots of oil on both solenoids! Old parts ended in 02, replacement parts end in 03.





Unrelated, but I noticed one of the bolts mating the transmission to the engine is only half-way in. I assume the chuckle****s at the dealer didn't torque this thing down properly on my 3rd transmission replacement.

Joec500

Nice! did you just remove the Wheels on each side to get access to the solenoid I remember when changing my plugs it looked relatively easy to access.

I am at 92k miles I may just proactively replace mine.

koala

Yep! Removed rear wheels, treated it just like a spark plug change as this solenoid is in line with the plugs.