Madpatt

Hi my name is Pat and I'm new to the Rennlist forum. I have a 2008 911 4s and it stalls when I come to a stop from driving it. It drops really low in rpm, it either tries to save itself or give up. It doesn't happen too often, but happened 3 times today when I was driving it around town. I also have a new interstate battery in it as well. The car accelerates well and cruises well, it's just the stalling part. I suspect that I can have a vacuum leak somewhere, but haven't come across it yet or some other issue I am over seeing. And it does have a check engine light.

I would really appreciate the help in resolving this issue!

Thank you!

Blu311

Automatic or Manual?

Did you get the check engine code read? If so, knowing that could help.

Hopefully someone will chime in soon with some help.

Sneaky Pete

Cam Actuator? I had those symptoms on my old 996. It was throwing a P1341 code.

Madpatt

Thanks for the quick reply. I hooked up the obd scanner and it brought up a few misfire codes. It's a manual. It will have a slight misfire in idle, but drives good. Now that I recall I took off the throttle position sensor off the intake when I was replacing the clutch. I haven't replaced the rubber ring, could there be a slight vacuum leak since I kept the gasket?

Sneaky Pete

What were the codes??? V leaks can cause crazy stuff.

semicycler

cracked coil packs? When was the last time you had your spark plugs changed out?

Madpatt

The codes are:

-P0300 (random/multiple cylinder misfire detected)

-P0303 (cyl 3 misfire)

-P0302 (cyl 2 misfire)

P0301 (cyl 1 misfire)

And I'm not sure when the coil packs were done last, if they were at all.

semicycler

All from the left/driver's side bank. You can DIY the coil packs without too much trouble. Two of the three on that side are straight forward. Jack the car, pull the wheel off, remove the heat shield over the plugs, pull one coil pack for visual inspection.

It could also be a vacuum issue on that side. Not sure where all the vacuum lines are though.

Madpatt

I also found this while doing my research.///

Generic OBD Error Code Details for P0300

Random/Multiple Cylinder Misfire Detected
What does this mean?
OBD Code P0300refers to
Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly. A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.

Symptoms
Possible sumptoms of OBD code P0300
the engine may be harder to start the engine may stumble / stumble, and/or hesitate other symptoms may also be present

Causes
Possible causes of OBD code P0300
A code P0300 may mean that one or more of the following has happened: Faulty spark plugs or wires Faulty coil (pack) Faulty oxygen sensor(s) Faulty fuel injector(s) Burned exhaust valve Faulty catalytic converter(s) Stuck/blocked EGR valve / passages Faulty camshaft position sensor Defective computer

Possible Solutions
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back. If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors. Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

Madpatt

Can someone explain why it's all missing on the driver side? What can there be going on there?

Craigw1926

Hi Patt. What did the problem end up being? I've got the exact same symptoms and codes on my car now, except my misfires are all 3 cylinders on the other side.
-Craig

Petza914

When the misfires are restricted to one bank it can also be one of the 2 O2 sensors on that side or the Cam Position Sensor for that side.

Madpatt

Thank you for the input everyone. Craig, I fixed it a couple weeks ago. It turned out to be a bad cam sensor. To diagnose, I swapped it with the opposite bank and the misfires followed it to that side. Replaced it within 15 minutes, problem solved!

Craigw1926

Thanks so much for replying (Patt and Pete). Slated for the shop on Monday morning, but if I can fix it myself before then......we'll that's more cash in my pocket to spend on fun mods.
-Craig

Craigw1926

A quick reply to update this thread. My car's problem with Rough idle and bank 1 misfires turned out to be the VVS actuator (or Vanos actuator, Variocam actuator) 9A1.105.308.02. My indy mechanic said Porsche has since updated the part to PN 9A1.105.308.03, which is an indication to him that they saw a need to change them for some reason. I just went ahead and had both sides replaced because my car has high miles.

It's a pretty strait forward job. Once you have access to the spark plug coils, you're there. The variocam actuators are right next to them.

The bummer is that he got a code for a bad actuator on bank 2 right after he plugged in his fancy PIWIS. But my cheap OBD2 only showed the generic codes for the misfires and nothing else. In this case, having a better diagnostic tool would have saved me from bringing it into a shop.