997 gen 1 2006 C4S misfire

[GKRPL1]

I really hope someone can help with this as I am now baffled. I have a 997 C4S Gen 1, 2006 model. I have had the vehicle from new and it has full OPSH. It is the 3rd new 911 I have owned so am quite used to them, the others were 996 C4S's. It is a coupe, 6 speed manual, Ceramic discs, UK spec right hand drive, all original equipment.

The problem is as follows. The "check engine light" comes onto the display with a "visit workshop" message in the display. Once on the yellow engine symbol and red exclamation mark cannot be cancelled without a reset by Porsche. The issue is that the car runs perfectly, never missing a beat. The fault codes stored are intermittent missfire on cylinders 4,5 and 6. The display also showed O2 sensor swapped bank 1 pre cat, so....

First job was to swap the coil packs, which were tired and probably due for a change anyway. Fault codes reset and all was well, until the next cold morning. Start up was instant and perfect until the choke cut off when the revs dropped to slightly below normal tickover and then it started missing. Light comes back on. Stop the engine and restart it and it's perfect - but the ******* light is on again! Codes are misfire on 4, 5 and 6 again.

Next was to replace the O2 sensor on that bank (carefully double checked by disconnecting the wiring plugs behind the tail lights, just to guarantee the convolutions of the exhaust didn't fool me as to which bank was 4, 5, and 6). Lights cancelled and all is well again - bear in mind the engine is still warm. Next cold morning - identical issue and light back on. Fault reads just the same.

I now suspect faulty coil packs (even original Porsche parts could have issues) but rather than buy new I swapped 1, 2 and 3 onto 4, 5 and 6. Fault cancelled and home. Same problem next day - back to the garage and the fault is....... on 4, 5 and 6. The car has had a four year service at 20,000 miles and the plugs were changed, it's now done 23,000 miles, but I suspected that now it MUST be plugs. Since it's a low cost spare I swapped to 3 new in cylinders 4, 5 and 6. Light cancelled and all's well to go home. Next morning same issue.

I now leave the car at the garage overnight, push it into the cold for an hour and then clear all the fault codes. I now start it with the KTS system plugged in. Fine untl the choke cuts off then intermittent missfire on 4 and 6. That was cancelled with the engine running, the engine note altered to a normal sweet running note and there are no recurring faults. The car was stopped, left to cool for 5 hours and the process repeated - exactly the same fault.

So - with the diagnostics in place each plug was switched off from the box. Instant missfire on whichever plug was disabled. Next the same for all six injectors (which are bomb proof as far as I'm aware on 997's, especially at such a low mileage) and the effect is the same. Missfire the instant the fuel is cut. Now you see why I am baffled. There seems no leak on the manifolds. No air hisses and no scorch/suck marks are visible. In any case the fault only occurs as the choke cuts and only until the engine is restarted in "warm mode". It is such a narrow band and neithere cold nor hot - it runs fine at both temerature extremes. Has anyone heard of a software fault? Has anyone experienced anything similar?

All help gratefully received, whilst the car runs fine the dash light is driving me mad.

Many thanks in advance.

Edited February 24, 2011 by GKRPL1

[PAULSPEED]

Sounds more like a simple air filter. The light comes on

when I have the oiled filter in and it is cold and wet. Put

a new paper filter in and the light goes away.

Are you running an oil filter?

Paul

[brahimza]

I have a 2006 C2S and like yourself, my check engine light would come on after the first cold start, not always but a few times a month.

At the end my car was taken to the shop and number of things were done to fix it,

clean out the lifters, if wrong oil is used, or oil has been sitting for a while it causes issues...

change the coil packs for the second time ( A few of the new packs had hair line cracks in them)

changed the plugs

Changed air filter

knock on woooooooooooood it hasn't happened for a year.

Good luck man, it is frustrating.

Edited February 25, 2011 by brahimza

[GKRPL1]

I have a 2006 C2S and like yourself, my check engine light would come on after the first cold start, not always but a few times a month.

At the end my car was taken to the shop and number of things were done to fix it,

clean out the lifters, if wrong oil is used, or oil has been sitting for a while it causes issues...

change the coil packs for the second time ( A few of the new packs had hair line cracks in them)

changed the plugs

Changed air filter

knock on woooooooooooood it hasn't happened for a year.

Good luck man, it is frustrating.

[GKRPL1]

Thanks Brahimza, your problem sounds very much like mine. I am now sure it's not the coil packs as they are both new and swapped side to side on the engine, with the fault remaining on the same bank. The oil is genuine Mobil 1 and was changed between services as a precaution, together with the filter - just in case! I now hope, as the previous reply to my post hinted, that it could be an air filter issue. Once half term is over I will take the filter out for a day and re run the test cycle after cancelling the faults. Thanks for your ideas and your good wishes.

[GKRPL1]

Sounds more like a simple air filter. The light comes on

when I have the oiled filter in and it is cold and wet. Put

a new paper filter in and the light goes away.

Are you running an oil filter?

Paul

[GKRPL1]

Hi Paul and thanks for your rapid response. I replied yesterday but can't see my reply in the forum, so I am adding this one out of courtesy if nothing else. I really hope you are correct and appreciate the suggestion very much. It could well be something as simple as that and I will remove the filter and re-run the tests to confirm this either way. The filter is the genuine Porsche item and was replaced in a main dealer service only 3K ago. However, it is such a simple test I will do it as soon as the kids are back at school. Ironically it does highlight a gripe I have with Porsche and their "easier servicing" statements. Why the air filter box cant just have over centre clips like most other vehicles I do not know! So many screws, on the base of the housing, is just crazy in my opinion - just thought I'd mention that too. Thanks again for your help.

[PAULSPEED]

The air filter is a pain but then that are why these cars

are special. Touch your maf sensor when you get it apart

and make sure that it does not feel stickie. Wipe it off

with a paper towel.

Paul

Edited February 27, 2011 by PAULSPEED

[997_rich]

Have you checked to make sure that you have a good ground wire from the frame to cylinders 4,5,6? that'll cause crappy spark and it easy to forget to tighten the bolt that holds the wire when you pull the wire for plug service. or maybe the wire is half-broken. without a good ground on the engine you'll get a crappy spark.

[GKRPL1]

Hi Rich and thanks for that tip. I have looked at the earth wire and it seems fine, however an easy check remedy will be to add an additional one, even if only temporarily. It will at least rule that potential problem out. In case other people that have been kind enough to respond are following this I can now confirm that the air filter has been removed, cleaned and that I have run the vehicle in the garage without a filter in - same issue exactly. So thnaks for the tip but I can now state for certain that it's not air filter related.

[PAULSPEED]

Sound like you have eliminated the air and the electrical.

All that is left is the fuel pump and lines. The only fuel filter is

in the pump. Maybe the pump needs to warm up before it

starts working right.

You could exam the pump or you could measure the pressure in the lines.

Last would be the fuel injectors. I had to replace them on my Nissan. They

had plastic caps that would crack.

Paul

[Loren]

Fault codes - fault codes - fault codes -- everything else is just guessing.

Please post the exact fault codes you currently have.

[VIR997]

I think I have the answer, or at least I hope I do. My 2005 C2 is in the shop for cold start misfires. Runs great, the only thing obviously wrong was the check engine light. However, the fault codes indicate random cold start misfires in all cylinders. I've had my software updated twice, plugs changed and compression checked. Interventions have led to the light going off for brief periods of time, from a week to as long as several months, but it hasn't lasted.

Turns out, a certain number of the 1st 2 yrs of the 997 (2005, 2006) have had problems with the lifters. A slow leak allows the oil to drain out over time, which causes the lifter to function suboptimally. If the car is cold, there will be misfires on startup until the fluid pressure builds back up in the lifter.

This is a documented problem that Porsche technicians should be able to look up. The fix appears to be replacing the lifters. I'm waiting to sort things out with my warranty people and am hoping this will fix my problem. Sounds reasonable enough to me. See if your mechanics think this is a possible cause for your problems.

[GKRPL1]

VIR997 I think you probably do have the answer! The symptoms you derscribe are EXACTLY like mine and the mechanics did mention lifters but deemed it unlikely. However pretty much everything else has been tried. The fault codes are always random misfires on 4,5 and 6. Like yourself various "fixes" have solved the problem for varying periods of time, a month, weeks, days and until the next start up. It is always perfect when warm so lifters will be the next job done - many thanks. I will keep everyone updated on progress. Loren and Paul Speed thanks for your comments too. The fuel and injectors seem fine and the fault codes are now stated.

Thanks again everyone.

Edited March 3, 2011 by GKRPL1

[Guest]

Bringing this thread back to see if anyone found a fix to this problem? I'm having a similar issue and hope the I don't have to fix the lifters ($$$).

[ltz5]

Morning Death (there's a statement I've never made before.....)

Going through the exact same issue. I have a 2006 C4S. 47,000 miles. (75,500 kms) Already tried, plugs, coils, O2 sensors, and filter. So after a month of adjusting things, changing parts, and resetting codes, I'm still getting random misfires on cylinder 5. Lifters could be next. Standby.

[Whistler805]

The dreaded "Check Engine Light" is driving me crazy.  2006 C2 here, only 30,000kms and I have had the light re-set 5 or 6 times now.  Seems to be a cold start issue, always cylinder 5 or 5 6 misfire, and recently "multiple misfire".  Plugs and 2 coil packs changed, ran great for 2 months, now its starting to act up, and oddly enough its getting cooler here.  I'm going to change the airfilter this week and see what happens, but lifter repair job sounds HUGE.  Has anyone had this done?  What was the cost? Maybe time to trade my 2006 C2 in? 

 

I seem to have a connection with cool weather, and moisture.  Don't drive mine in the rain ever, but got caught a week ago while away.  After it sat in the rain for 2 days (never do this), it was running really rough until it warmed up for 30-40 minutes.  So rough, I thought I would need to call for a tow truck, then suddenly, it started to purrrr and run perfect again.  Like to hear if anyone has sorted this problem out, or if the lifter job worked and how much.

[Loren]

The dreaded "Check Engine Light" is driving me crazy.  2006 C2 here, only 30,000kms and I have had the light re-set 5 or 6 times now.  Seems to be a cold start issue, always cylinder 5 or 5 6 misfire, and recently "multiple misfire".  Plugs and 2 coil packs changed, ran great for 2 months, now its starting to act up, and oddly enough its getting cooler here.  I'm going to change the airfilter this week and see what happens, but lifter repair job sounds HUGE.  Has anyone had this done?  What was the cost? Maybe time to trade my 2006 C2 in? 

 

I seem to have a connection with cool weather, and moisture.  Don't drive mine in the rain ever, but got caught a week ago while away.  After it sat in the rain for 2 days (never do this), it was running really rough until it warmed up for 30-40 minutes.  So rough, I thought I would need to call for a tow truck, then suddenly, it started to purrrr and run perfect again.  Like to hear if anyone has sorted this problem out, or if the lifter job worked and how much.

 

:welcome: 

If you want to know what is going on you will need a Porsche specific diagnostic tool like Durametric or find a shop with a Porsche PIWIS or PIWIS 2 tester.

Have them do a complete diagnostic report back the fault code(s). Post those here and we can make recommendations.

Without the fault codes everything is just a guess (and those can get expensive).

[jemi]

Did you get this resolved?

 have similar symptoms on my Porsche 996 C4S, I had the Variocam actuators replaced, and the misfire was cured, 3 months later the same fault codes and a very sporadic misfire has occurred.... very frustrating

 

P1371 - Valve lift control checksum error

P1360 - Valve lift control Cylinder 6

P0300 Misfire detection (total)

P0306 Misfire Cylinder 6

 

Any suggestions?