kingian65

My 2005 Porsche 911 997 Carrera has a chronic problem. The check engine light comes on at cold start and never goes off unless I clear the codes with a code clearing device. The code is p0300 and goes all the way to 301, 302, 303,304, 305 and 306. The indication is random misfire codes. I have taken the car to an independent shop and two dealerships. I have replaced the spark plugs twice, new coils, smoke test for vacuum leak, new aiflow meter, and they have also checked and tightened the harness. The light still intermittently comes on, which means the car cannot pass Pennsylvania state emmissions inspection. The dealer does not think it is the computer (which is covered by warranty) so they will not replace it. The dealer has had the car in the shop for two full months and cannot remedy the problem. When the car starts cold, the engine runs a little rough and then the check engine light comes on. After a few seconds, the engine runs beautifully. If the codes are cleared after the engine is warm, the light does not come on again until another random time it is started cold. The problem has been going on for years, and the gasoline used is either Exxon Premium or Shell Premium, both recommended by Porsche. The dealer has it for a long time because he can only try to diagnose the problem on cold start, so has to wait overnight after an attempted fix to see if the engine will trigger the code. I have never had this problem on any car I have ever owned. Is there anyone else who has had this problem and solved it for good? As it is, I cannot pass Pennsylvania State Emmissions Inspection and certainly could not sell the car in good conscience.

BED997

You vaguely alluded to having a warranty?? - What are the stipulations around the lemon law in your state if the car is under warranty?

"Although each state imposes different requirements for their own consumer lemon laws, a basic condition common to virtually all jurisdictions is that in order for the lemon law to apply, the automobile or product must have been purchased with a warranty.[2] Products purchased on an "as is" or "with all faults" basis are typically not covered by state or federal lemon laws."

"State lemon laws vary by state and may not necessarily cover used or leased cars. The rights afforded to consumers by lemon laws may exceed the warranties expressed in purchase contracts. Lemon law is the common nickname for these laws, but each state has different names for the laws and acts."

neanicu

They might need to start thinking further in terms of diagnostic. When the CEL is on,you check fuel delivery and ignition as the most common problems,but the CEL could also be triggered by a mechanical problem(valve lift fault,Variocam etc).
I believe they're not considering the DME to be at fault because the CEL gets triggered by an existing rough idle when cold.

McCulla

Kingian65, you've got a kindred spirit here. Interestingly, I bought my car used a couple of years ago in Penn! (I'm in FL); last time my CEL was a huge problem was about 11 months ago and 3 weeks and $7000 later, the lifters were all replaced. It was a night mare to diagnose. All was good until about 3 weeks ago and it's happened again. Same codes as you, they had the car for a week (indy shop) and can't figure it out. My car has about 50K miles, is also an 05. The tech has given me back the car to drive because it drives fine. He is doing some research on the ECU/DME now. Mine behaves just like yours. Always cold start. MAYBE slightly rough, but not truly perceptable. I'm ready to sell the car if they ever get the CEL figured out. It's my daily driver and I need to be able to depend on it, but nobody is going to buy a car that has a steadily lit CEL, obviously. I will probably try a dealer if the indy can't figure it out....frustrating.

jhbrennan

Sell or trade to a dealer.

Little Green

I was thinking lemon laws. Maybe a call to PCNA is in order?

Graygoose997

You aren't going to get anywhere with a lemon law complaint on a used car, or a 7 year old new car purchase with the legal system.
If it's a Porsche CPO warrantee , it's Porsche you need to talk to.

buddy911t

I have an 05' Carrera. My CEL came on and stayed on until the dealer got it. After much investigation and consults with Porsche it was determined it was a problem with the lifters. they replaced them all including the guide structure that the lifters run in. This was all done under warranty since I'd just bought the car. It has run perfectly for 10,000mi since.

JW911

You're scaring me. I have reset my CEL a couple of times using my durametric. But never able to identify a problem. I have new coils and spark plugs. So I know that is not the problem. Lifters sound very expensive.

buddy911t

Sorry for the scare but coils and plugs were the first thing my dealer tried. It was fine for a short time then cel came on once again. It didn't stay off till the valve lifter work was done. I had very bad mileage 13/14 mpg while this was going on. I don't know the final cost of the work but they did have to drop the motor. You may have nothing to worry about but I would suggest your mech. consider this possibility. Good luck to you and I hope it's something small.

McCulla

See my above post regarding the cost of lifters. The diagnostic attempts were pretty damn expensive due to the number of darts thrown at the dart board! I don't have the receipt in front of me, but the total was nearly $7000. The lifter replacement probably made up $4000+ of that total. Luckily I have an aftermarket warranty that paid most of the non-diagnostic portion, but they have a limit on how many paths they'll pay to walk down trying to find a problem. I am completely fine with that, but this particular problem is very obviously difficult to pin on one certain thing. That's why I'm not very happy that I'm having to do it all again. BTW, my car ran fine for about 12K miles, before the CEL came on again.

McCulla

As a follow up, as of now (2 weeks in), my indy had tried new coil packs, no help. Tried switching injectors, no help. Looking at the ECU as I mentioned. No solution yet.

TerpsRED

Since it is a cold start related issue, could it be something to do with the MAF sensor or the catalytic converter sensor that the car uses to determine cold start timing and RPM flow?

Just a thought for pieces that you don't need to tear down the engine to try.

Macster

If the car is under warranty you need to push to get this resolved.

Consider this: The car is a Porsche. You took the car to a Porsche dealer. It can't throw up its hands and claim it can't or doesn't know what's wrong.

I suspect however the warranty you speak of is the emission warranty and the dealer is right. The DME is covered, the converters are covered but not much else.

Now then.. the error codes... P0300 is general misfires and of course the other 6 codes are misfires for all 6 cylinders.

This happens at cold

New plugs.

New coils.

Have you tried disconnecting the MAF and seeing if the symptom appears?

As others have mentioned I suspect the problem is in the lifters or in the VarioCam Plus system.

The dealer can test this and I believe confirm this is going on (or not). But at least you would know.

Now the lifters are by themselves, well, individually, inexpensive, but the labor to replace them (or even one) is not.

I would contact the PA emissions agency and lay out the situation and ask if it can offer any suggestions. You want to comply, you expect the car to comply, but it does not and why shouldn't the cost to bring the car into compliance not be covered by the emissions warranty?

You want an estimate of the cost parts/labor to replace all intake lifters and just to be safe the cost of replacing the VarioCam Plus system components, which are (WAG) actuators, solenoids. These are expensive (hundreds of dollars each -- I paid around $700 for the actuator on my 02 Boxster) and the labor to remove/replace these can run maybe 8 hours per bank to replace, maybe more (if for instance the engine has to come out of the car). You need a hard/high confidence quote, though, not just the WAGs of me on my 2nd cup of coffee.)

Often in this case though just the lifters are replaced.

The primary reason is they have gotten dirty somehow.

But given the misfires are in all cylinders it is possible that more the dirty lifters are the cause of the misfires.

halik

Could also be a small vacuum leak that seals once engine metal expands. What are they seeing on long term and short term fuel trims?

Also as far as lifters go, you can try some of that AutoRX stuff as last ditch effort (in case something got into them)