JFP in PA

More to the point, it looks more like you may need to replace your mechanic,First of all, there are a lot of thing on the exhaust, like multiple heat shields that are famous for coming loose and rattling, so I would not immediately start thinking about replacing the expensive cat until appropriate diagnostics say you actually need one. As for the codes, P0446 points to a problem with the EVAP canister shut off valve on the intake purge line, which could also cause a vacuum leak. P1124 and 1126 are both O2 sensor codes that indicate that your intake system (which is attached to the EVAP purge line) has a vacuum leak because the DME cannot enrich the mixture enough to get the fuel air ratio back in spec. None of this points to bad cats, just a problem valve and possible resulting air leak, and some otherwise poorly executed diagnostics.

I'm not sure the Durametric can help you with this, it may require a PIWIS.

The VIN look up is for contributing members, perhaps now would be a good time to consider donating and becoming one?

Try rotating the engine another cycle and then check it; it should be at TDC with the pin in.

Sounds more and more like a lifter issue. Check with your local PCA chapter for a list of suggested shops in your area.

First, welcome to RennTech :welcome: While you are waiting for others to respond, let me assure you that the IMS problem is not a figment of someone's over-active imagination. There have been a substantial number of failures in the M96/97 engines, currently estimated to be somewhere around 1% of all dual row style IMS bearings (1997-2000) and upwards of 10% for all cars produced with single row bearings (2000-2005). These are Porsche's own numbers from the class action lawsuit settlement, which you can locate online if you search. The 2005-2008 cars, which use yet a third design IMS bearing also suffered failures, but the actual rate has yet not been published, but it is worth noting that Porsche eliminated the IMS shaft and bearing from all their engines with the 9A1 design engine starting in 2009.

Forgive my ignorance on this, but what "rollers" are you referring to? The other pulleys in the serpentine system.

Loose plugs can make all kinds of sounds, depending upon how loose they are. You would get anything from a tick like sound to a screeching sound. Plugs should be torqued to 30 Nm +/- 3Nm, or 22 ft. lbs. +/- 2 ft. lb.

You really have had to hear both to sense the difference, lifters make a sharper "tick" while bad cylinders tend to make a duller sound. Jake's description of where to place the stethoscope is a good one as it would localize the sound.

Porsche uses hydraulic cam followers with rather small oil passages in them that are prone to blockage and varnish like build up as they form a kind of "dead end" for the oil passages. I have not seen an additive that would help with that problem.

According to the parts system, you should have a free wheeling pulley on the alternator. That said, if the car does not have one, and you are not the original owner, it may have been changed out at some time.

If he would like to PM his VIN to me, I could tell him what is supposed to be in the car.

Porsche parts list the alternator both ways in 1999, so it did exist with the free wheeling pulley that year..

I wonder if those sensors are not applicable to my car since the values never change? The other fuel trim readings seem normal. If you take a look at post #5, I took a photo of the diagnostic screens that my reader has when it's hooked up with the engine off. It shows the above two readings for the sensors that stayed fixed as well as the other fuel trim readings that seemed to be changing appropriately with the diving conditions. Are the readings for STFTB1S2 and STFTB2S2 supposed to change? The spark plugs used on the car (according to the receipt) are: (7410) FR6LDC (I think he meant to write LDU not LDC) Those should be correct according to the manual, however I don't know the torque they used since it was a shop that did it before I owned the car. They were done 3 years and 7,000 miles ago. I thought that I read somewhere that cars with a performance tune (I have the Ultimate Motorwerks tune) eat through spark plugs much quicker and it may help to go with one step colder. Is there truth to that? Couple of thoughts: Yes, most "tuned" turbo cars benefit from running at least one step colder plugs. Secondly, have you tried measuring the same fuel trims but using a Porsche specific scan tool (Durametric, PST II, PIWIS)?

Center of photo:

That voltage should be more than enough. One item to consider is your brake light switch; there have been multiple reports of failing brake light switches causing ABS and/or PSM faults which promptly went away when the switch was replaced.

I've seen failed mounts, but I was wondering if there is an easy way to see, or test them on this actual car. I didn't look at them carefully. Maybe I can just grab the engine and shake it to see if it moves? If I am correct, they should be very easy to change on this car, right? I have a lift in my garage, so that should make it even easier. I'm not near the car now, so I can't look now. It's very possible that the mounts are bad because I always felt that the car idled a little rougher than I thought it should. I was just under the impression that it was normal because everyone says that they are a little rougher than the Boxsters and that's what I compared it to. I had a 2001 Boxster S You will need to support the engine while swapping them out, and may find that access from above may be restricted by some stuff that is removable, but they are not overly hard to change out: There are also multiple aftermarket vendors of "improved" mounts that use replacement materials like urethane to improve their strength, but also tend to impart higher vibration in the process. Because the turbo engine is a race derived unit, it shakes a bit more than the more pedestrian M96/97 street engines. If the mounts are really bad, you can usually see the engine move when someone revs it.

And these are the actual engine mounts:

Usually the rubber in the mount is either torn or has sections totally missing. This happens to be a transmission mount insert, but it will give you the basic idea:

There is no problem with the way it runs, or the sound. Everything I'm complaining about has to do with the feel. It just feels like a rough or unrefined engine for a little while after a cold start. The RPM's start that high (~1,200) but after warming a little, they settle down to 800 rpm. There are no drivability issues. All of the turbo cars have a bit of a lumpy idle when compared to the normally aspirated cars, but many times idle vagaries can be traced to failing motor mounts. If it was a failing motor mount, wouldn't it vibrate all the time? I guess it does feel the same as a bad mount, but it only does it for a short time and only on a cold start. The idle doesn't stay there. That is only when it is initially started cold. It settles in at 800 rpm, which I believe is perfectly normal. I agree, it seems to be a very difficult troubleshoot, I'm usually very good at troubleshooting, but this has me stumped! My best bet is probably to go to a mechanic that knows these cars very well so they can check it out. For all I know, it may even be a normal characteristic of these engines. Bad engine or transmission mounts usually show up only under certain circumstances, which is why they often get overlooked. When the engine is "loping" at idle, it is really trying to move around quite a bit, so a weak mount would make if feel even worse than it really is. I also would expect the car to normally run at higher RPM's than the regular idle speeds on a cold start.

All of the turbo cars have a bit of a lumpy idle when compared to the normally aspirated cars, but many times idle vagaries can be traced to failing motor mounts.

I would have to agree with jpflip, your first step should be to try recalibration of the steering system before spending any money.

As you will most likely be altering the vehicle's tire aspect ratio (http://www.yokohamatire.com/tires_101/reading_your_tire/aspect_ratio/) when you make this type of change, things such as ride height, quality, and steering response will also change in response to the stiffer sidewalls on lower profile tires.

The codes you might see are not specific to the belts, only that the airbag system is faulty.

Any pending codes would have appeared with the active codes. I would have to agree with RFM's assessment, you may have to test voltages when the fault appears.