logray

Certainly if the tires are worn or worn unevenly it can cause vibration. Or tire pressure, road surface can contribute. Then balance. Then alignment.

IIRC the early IPD plenums were painted, but the new ones are not.

Certainly if you clean the IACV, TB, MAF, fix intake leaks, etc. that can clear up searching. But if he is getting rough idle along with those codes, the actuator is probably stuck. Sorry to the OP if I missed this, but what model year if your car? If it is an 2002 or later the repair procedure is much different than 1999-2001 cars. Also, something to try. First ensure the oil level is proper. Then take it out for a good thrashing/spirited drive. Sometimes the actuators or vane adjusters can get clogged up and a good drive or two has been reported to "ungum" them.

I'm not sure about the cat removal on a Boxster, but why not source a used cat if you plan to "shotgun" it? $600 for example at dcauto.com. I'm not sure what you mean by which cat. Or by "rear one" do you mean the silencer/muffler? There are only two cats on the car. Not sure if your MY but if it is for 2002 or less here are the part numbers: 99611302306 99611302406 I would still stick to JFP's plan though, and fix the 2ndary air problems first, then clear the codes and then go for the cats. At least on a 996 it is very simple to remove a cat, about 6 bolts to loosen off, and it drops straight out.

The rough idle is because the actuator is stuck "on". Above about 1700-300rpm (depending on conditions) the engine will run smooth again. Likely the variocam actuator needs to be replaced, or at the very least variocam solenoid. Both require removing the camshaft cover and some special tools. Do-able without removing the engine, but easier with the engine dropped. You can try to clear the code, it won't hurt. But if the actuator is still "broken" the CEL will come right back on.

The IACV is operated by electromagnet. You can safely spray carburetor cleaner or equivalent inside the ICV and use a towel or rags to clean out.. Be sure that it drys completely before reinstalling. You really do not need to open it up to clean it well. I remember driving on the German highways 10 years ago in a BMW 5 series, it was a lot of fun driving that fast and I miss it. I have heard though that the traffic gets bad. I will have to go back to Germany some day, but my German could use a refresher! Last year in Italy and France was fun too. France has some great country roads.

You can clean it without opening, but you have to remove it from the throttle body (careful not to damage the paper gasket, but it is cheap to replace if you do). Some people have gone a "step further" and pressed out the pin and dismantled it to clean it, but I don't think that is necessary.

Also search for boost spring or clutch spring...

I remember reading about a company who sold aftermarket paddle shifter set for the 996 or 997 tiptronic... so it might exist, but sorry I'm short on the details or links.

This might help? http://en.wikipedia.org/wiki/Porsche_993#Production_figures

Yes, they are inexpensive. Here is a post that might help you: You are not supposed to re-use them, they are single use stretch parts. The rod bolts are known to be a weak link on this car. If you re-use the head bolts and they fail, then your engine is ruined, same with the rod bolts. The rod bolts are very inexpensive, so not sure why you would re-use them. The head bolts are more expensive but if you have already disassembled your engine, the cost is probably not much greater than what you already have to spend on all the damages. You might try searching for a procedure to verify timing for an IMS bearing retrofit on a 3.6L, I can't find any good websites either regarding timing the 3 chain engine.

Should not be any play other than rotational...

Hi there! Thanks for the very descriptive post. As for the fans, I believe with a 997 you can unplug the stage 1 relays and then verify that the stage 2 fans click on. If you turn on your air con, the stage 1 fans should come on. If you own a durametric this can activate stage 1 or stage 2 fans with your laptop. 100c is not abnormal. Certainly clean your radiators and be sure your coolant tank is topped off to max level (add distilled water if it is low). The engine bay fan only clicks on when it is really very very hot (Africa hot). If a fan isn't working on one side it could be a ballast. As for the drive belt, if you hear abnormal noises, you can remove the belt the run the cold engine for just a minute or so. If the noises are gone, then likely the noise is related to the belt itself or one of the accessories (i.e. aircon, power steering, idler puller, water pump, generator). While the belt is off you can spin the pulleys around by hand. There should not be any play other than rotational and they should not make noise. Do check that all of your fluids are topped off. As for the ticking sound, this could be a variety of issues. Loose exhaust, wrong or low oil, damaged internals, etc. Too many to list in fact and they are all just guesses. Best thing is to check the oil is adequate and the proper viscosity. Post a video or recording of the sound and that might help isolate the issue. Lastly, if any of this sounds to difficult or doesn't make sense to you, certainly don't hesitate to pay the money for a professional inspection. On your model year car, it is worth much more than the cost of a replacement engine, even as a roller (sans engine).

... I posted incorrect info posted...

Search on google or here "pioneer avic 996 diy", there are plenty of step by steps including part numbers out there.

If you see a little oil there, I don't know if that means your AOS is going bad. It's hard to say from the pic how much oil or how long the oil has been there. Have a look at this post:

Really hard to tell from that pic But it looks like it is the AOS breather/vent on top of the 4-6 head. It is normal for that to weep a little, but not severely. I would just clean it up as best you can and monitor. That is a pain to get at with the engine installed and there are two rubber orings inside of the connector which could also be the source of a leak. 99610704751 p/n

The issue I see here is that the misfire(s) or poor fuel or spark delivery could have already caused a problem with piston rings or ring seal in that cylinder. It could have been that the rings were not seated well in the first place and had nothing to do with spark/fuel and this cylinder has always been down on power. In any case, if there are no problems found with the valves, and you are still seeing low compression on that cylinder, then the only things left could be problems with the cylinder itself or piston rings. The damage is "done" so to speak. About the only last possibility aside from tear down and rebuild might be trying an oil change with straight break in oil, for example "SAE30 break-in motor oil" for a few hundred miles and trying to get better ring seal by following a procedure such as this: http://www.mototuneusa.com/break_in_secrets.htm. It might be worth a few compression points, but would it be enough to bring that cylinder to within "healthy engine" status, I'm not sure. Have you used a boroscope on cylinder #5 to see if there is any cylinder wall damage (for example scoring)? A car with such low miles though, if it is under warranty and Porsche is willing to replace the engine: that would be about the only way I would consider repairing this. I have read about warranty replacement engines for cylinder wall scoring or other issues similar to this. Sine the car has great power still, and the cost to rebuild the bottom end and replace the piston rings is very high... If the car is out of warranty, I would just continue to drive the car until it really does need a new engine or major rebuild.

Are you sure the sound isn't just the sound of fluid being pushed or pulled as you rotate the pulley by hand?

Yes based on the better test results after adding oil, that typically means the piston rings are not sealing as well in cylinder 5. The leak down test should help confirm where the problem is, whether it would be with the valve seals/guides/seats or the piston rings. I have been told though by a few reputable engine builders that you cannot expect typical results from the Lokasil cylinder wall material, although your tests are following convention. What year is your car?, if it is a 3.6L then the cylinder walls are slightly improved over older 3.4L models and the piston ring problem could be a symptom of another problem (such as clogged fuel injector/bad spark/etc.)

It sounds like the car is in pretty good shape if that's all they are reporting. The camshaft/valve covers are actually sealed using silicone (Loctite 5900), not a normal cork, paper, or metal gasket. While it is possible for this silicone to leak, it is not as common as other reasons. Each of the 23 cam cover bolts have the opportunity to leak as well, if the application of silicone was not proper. Removing the camshaft covers must be done with great care and a special camshaft locking tool and bolts removed in a certain sequence. Then correct torque sequence applied. It is not very easy to do with the engine in car. Of course, once you open the cam cover on a 2002, you might as well replace the 4th and 5th timing chains and variocam ramps. A more common reason for oil present on the camshaft cover is spark plug tube orings, which certainly do dry out and lose their seal over time. As was stated earlier this could be a leak from the rear main seal or intermediate shaft seal. Repairing both are common practice, not actually as bad as they may sound, but do require removing the transmission which is probably the most labor intensive part of the job. I would use those two items to leverage the purchase of the car by about $1500-$2500 USD in order to make those repairs.

You can use the same oil you put in the car, but it shouldn't matter that much. In a small oil can I would squirt 2 or 3 times at most. The oil will burn off once combustion happens.

Glad you got it sorted. There was a fellow on here earlier that also had huge intake leaks and it was causing misfires as well.

On a cold start idle, how much does MAF really play into the running of the engine though wvicary?