Stefan

No need for a new starter. Take the old one out, lube it, and put it back. It's a fairly easy job.

Another possibility is that your fuel injectors are dirty/clogged. Try using Techron fuel system cleaner.

The paper clip has to go in straight back and it can't be a thick paper clip.

I had declining MPG and the problem turned out to be worn out primary O2 sensors. They didn't throw a code but replacing them caused the MPG to jump up significantly. What's the mileage on your car?

I've read that the most effective place to put sound deadener to reduce road noise is in the wheel well.

The cats are actually much newer than the rest of the car. I'd estimate they have about 40k miles on them. If they weren't functioning efficiently I would think the secondary O2 sensors would detect it and a CEL would be triggered.

I guess I'm surprised that the secondary O2 sensors' output is important for anything other than generating a CEL since my understanding was that the European cars don't even have them. Since these sensors on my car are well beyond their expected lifespan and the primary ones were definitely bad it is a fair assumption that theses are too.

Since one of my other suspects is leaking injectors that article is helpful.

But regarding this question, which is about the secondary O2 sensors, I don't see anything there. The mixture adjustments are done based on input from the primary O2 sensors. As far as I understand, the secondary O2 sensors don't contribute anything. I am looking for confirmation on that fact so that I can eliminate this as a possibility.

I have a 1999 Boxster (wait, don't kick me out of this forum yet) with a 1999 3.4L 996 engine.

I am having trouble tracking down a rough running problem (detailed here http://www.renntech....n-engine-warm).

My secondary O2 sensors are quite old (145K miles). They aren't giving off any faults. Nor were the primary O2 sensors but when I replaced them, my MPG went up significantly.

Is it possible for poorly functioning secondary O2 sensors to affect the way the car runs? Or are they simply to test the efficiency of the cats?

I finally got two codes,

P1127 Oxygen Sensing Adaptation Range 2 (Cylinder 1 - 3) Lean Limit.

P1129 Oxygen Sensing Adaptation Range 2 (Cylinder 4 - 6) Lean Limit.

So now I'm going to recheck the fuel pressure regulator, its vacuum lines, and the fuel return line.

Another possible listed cause of these codes is leakage of the fuel injectors. I have to assume they're referring to air leakage because I can't see why the car would be running that rich unless air is being lost from the system.

--

This is also particularly interesting since I was initially trying to chase this down by looking for a leak in the intake system. But that would cause a lean condition, not a rich one.

I send JFP's comments. I replaced the factory fill in my 1999 Boxster with RedLine. I read all about it online and spoke to a RedLine rep who insisted that it would work well. Nevertheless, shift quality was noticeably worse. I gave it about 10k miles then gave up and went back to factory fluid and the problems have completely gone away.

Glad you like it. The suspension will settle. Give it a few months.

20 (951)

Start by checking the cable alignment using the $5 Porsche part from your dealer. Also, you might want to try using the search function as this topic has been covered numerous times.

I had the same identical problem. I replaced the electrical portion of the switch and there was no improvement. I tried all manners of cleaning and lubrication and was able to only slightly improve the behavior but never to my satisfaction. Eventually, I replaced the cylinder and the problem is now 100% solved.

I got the updated part from Suncoast Porsche for $119 (http://www.e-partssales.com/miva/merchant.mvc?Screen=PROD&Store_Code=P&Product_Code=99634701707)

I have read all the posts in this regard and appreciate them,,,,,my problem is that i have already replaced the ignition switch on my '99 996 with Porsche part #4A0 905 849 B and my issue persists,,,ie. which is that I hear a delayed clicking sound anywhere from a few seconds to a minute or so after i remove the key from the cylinder,,,the time delay seems to be a factor of temperture,,the colder it is, the longer the delay before the 'click,,,it sounds like the (a) tumbler falling into place,,,I have now, yesterday, also began experiencing the key becoming difficult to remove,,,do you believe I may either/also have a problem with the cylnder itself, or does this still seem like the switch?

Easiest is to start by checking the relevant fuses (B1, B10, E1).

I had the identical problem (loud periodic squeaking noise when lowering the window) and I fixed it by lubing the heck out of the roller from the top. I used Wurth HHS 2000 (great stuff) and it took several applications before the sound was gone.

I really wish I was getting a code because that would make diagnosis much easier. I'm thinking that it can't really be a misfire because the engine management system is good at detecting those.

At idle...

MAF

17.45 kg/hour (idle).

I haven't checked the reading at 2500 but I know that the value does go up (i.e. the MAF isn't totally broken).

Note that I am using a 560 ohm resistor on the signal wire. Using a 330 ohm resistor, it was 19.05 kg/hour.

I doubt that the MAF is the cause since when the MAF is unplugged the rough running behavior is identical.

FRA and TRA

0.73 (FRA and FRA2)

0.24 and 0.2 (TRA and TRA2, respectively)

They seem steady at idle but the Durametric rev 1 refresh rate is quite slow IMO.

Pre-cat O2 sensors

0.91 - 1.04 (cycling up and down, same range for both sides)

Do you happen to know if using Propane around a cracked oil filler tube bellows will cause idle to go up? I haven't eliminated a crack in that as a possibility. I haven't been able to see a crack and wiggling the hose doesn't affect the rough running.

Replaced the AOS bellows since I happened to have an extra lying around. The problem persists. :(

Note that according to Porsche TSB #2870, the Beru spark plugs are no longer recommended.

As of MY 1999.

Spark plug types:

New: Bosch - FGR 6 KQC

Previous: Bosch - FR 6 LDC -or- Beru 14 FR 6 LDU

A bearing puller is required. There is no way you can accomplish the task with a drift. It's by no means simple but it's not super hard either.

My car is a 1999 Boxster with a 1999 3.4L 996 engine. The car has 140k miles. The engine has 84k miles.

The has a problem for several months now. When I start the car cold, it always runs perfectly but as the car warms up the idle gets progressively rougher. When the engine is running rough, the entire engine shudders and it sounds like misfires but there are no codes. The problem is intermittent. When warm, the car sometimes idles perfectly. The car goes from idling smoothly to idling rough randomly. I have never gotten any CEL codes since this problem started happening.

Using a Durametric, I confirmed that the "rough running" parameter fluctuates when the problem is happening.

Things I have eliminated:

(1) MAF - problem happens identically with the MAF unplugged

(2) Ignition coils - all checked, no cracks or other visible problems, plugs snapped in properly

(3) Pre-cat O2 sensors - I just replaced them and there is no change in idle behavior (although car gets significantly better MPG)

(4) Intake leak - I checked the entire intake and vacuum system for leaks - nothing found (and idle doesn't go up when the problem occurs)

(5) Resetting mixture parameters - I have tried this a few times after various experiments - no change

(6) Lower fuel injector o-rings leaking - I replaced these - no change

(7) Clogged fuel injectors - ran Techron fuel system cleaner through - no change

(8) Idle control valve - I have cleaned this and the flap moves fine. Also, idle is rock solid even when engine is running rough.

Suspects:

(1) Spark plugs. The spark plugs are relatively new (about 10k miles). I took them all out and they all look fine (and identical to each other). The plugs I'm using are the ones from AutoHausAz (Bosch 4-electrode).

(2) Post-cat O2 sensors - They are 140k old but there are no codes and I didn't think these sensors affect mixture (right?)

(3) AOS bellows - I haven't checked this yet but I replaced the AOS and bellows about 25k miles ago and the problem started happening well after that.

(4) Upper fuel injection o-rings - I didn't replace these because it requires removal of fuel injectors (read: fuel everywhere)

---

Any comments or help on what else I should check or how to further diagnose would be greatly appreciated.

You most likely do not need a starter. Several of us have had this identical problem and have fixed it without too much effort.

There are TSBs from Porsche on many different rattles. I suggest you start there.

It looks like I will be giving the Redline 75W90 NS GL-5 a try.

FWIW, I used that in my Boxster and it made the shifting much more notchy. I had spoken to Redline on the phone twice to clarify that this was what they recommended. I replaced it with the factory fluid and the shifting was good again.