misfire at 4000rpm

[MikeO]

I've just bought a 1998 996 (3.4) from a leading independent specialist. It had a full inspection and service before I picked it up (and they did spend some money on it (new discs and pads, air con condensor etc). However: I've noticed that intermitently there's a stutter in performance, accelerating hard, just as it passes through 4000 revs. Is this just one of those things, or dirty petrol, or is it something I should get checked out?

 

[Guest]

I've had my 996 (3.4) C4 for 6 months and covered the full rev range. It has never been anything but smooth, no hesitation. I think you should have your car looked at. Do you have any warranty cover from the dealer ?

Hope it's nothing serious.

Will

 

[GreigM]

Mike - regardless if you got a warranty or not - if you bought from ANY sort of car dealer you get a months full warranty - law I believe, so get them to sort it pronto.

 

[Melv]

Coil or air mass sensor -get the dealer to sort it.....

Mel

 

[TISPKJ]

Mike, No help I know but mine does the same !

I am waiting for porsche to sort it under warranty along with the cam cover gasket replacement on my 98 C2.

Please post when you find out what the problem is for sure or call me on 07710 -960695

Many thanks
Paul

 

[MikeO]

I've got it booked in now for 24th May. I'll let you know what they say. Thanks.

 

[TISPKJ]

Mine for the 26th .............

 

[MikeO]

Typically over the last couple weeks the problem's faded, but it still seems to be having odd misfires and flat patches.
I took it in today; the diagnostics hadn't logged any faults, there was a loose clip on one of the spark plugs, but this didn't seem to make much difference. The next stage is to try it with a new air mass sensor - but they didn't have one in today so I'll take it back probably next week.

 

[TISPKJ]

Thanks Mike, mine goes in tommorow and no doubt they wont be able to sort it either or it wont do it, the car just seems so slugish after about 4000 rpm.

Im not sure where the air mass sensor is, but if it is the lead that plugs in just before the inlet butterfly i did pull it off on Sunday cleaned it (only the lead) and put it back on again, seemed to make a difference but maybe I imagined it, sometimes you drive the car and think ... wow, and other times you wonder what all the fuss is about, like I say slugish. I have only driven a newer 3.6 01 996 to compare but it seemed so much quicker everywhere.

Will let you know

Regards
Paul

 

[steve lyden brown]

I noticed in June's edition of Porsche Post that the 996 Registrar ( I think his name is McGirl ) seems to have bought a brand new 996 which comes with a switchable sports exhuast. Does anyone know anything about this type of exhuast ?

Having put a deposit on it last week, I collect my new (to me) 996 Cab Tip this Friday. Can anyone tell me if the toolkit issued by Porsche when the car was new is likely to have any specific or unusual tools in it that might only be relevant to the 996, especially the Cab version. I ask this since my 964 Cab had a weird tool for raising and lowering the hood if the power failed.
Steve.

 

[TISPKJ]

Steve, the porsche sports exhaust is a factory option but can be retro fitted at aything up to £1500, the sound though is superb !!

I am currently in the process of modifying the standard system to sport specification but this will not be switchable like the factory item, I am nearly ready to offer these on an exchange basis to other club members for sensible money, if your bored with the washing machine sound of your 996 give me a shout.

Regards
Paul

 

[steve lyden brown]

Thanks, Paul me old mate, for your offer on a sports exhaust, but as I understand it, my 996(which I have yet to collect) has one already. How can I be sure, do you think ? The other thing that puzzles me about the Sports exhaust on the new car bought by Mr.McGirl, is tha he describes it as being"switchable". Do you think that this means it can be on or off depending, say, if one is putting it in for an MOT, or whatever !
The other thing I'd like to check out is that my 996 is described as being an 'S' model 996 Cab Tip C2. Does anyone know what the **** an 'S' model is ?
Cheers,
Steve.

 

[Guest]

Paul - tell us more about what you have in mind.

Steve - I think he means 'S' registration ....

 

[TISPKJ]

Mike finnally found out what the problem with mine is, it's the variocam sender unit not working, hence it never really gets on the cam just goes flat at 4000 rpm instead of ballistic !! get them to check it out for you on the diagnostic machine and make surethey rev it to 5000 or it wont pick up the problem by just pluging it in. Course they havent cured it cos they havent got the bits in stock !! no suprise there eh, still they only had it 3 days !!!.


Steve, the switschable system you refer to is as it says switchable, you have a switch on the centre console that opens and closes a valve in the exhaust so you can have it as open sports type system or zanussi washing machine replica like standard, it's superb mate, well done. S refers to Tiptronic S which means the controls for changing gear are on the steering wheel, It's not relevant anymore to my knowledge as they all have touch change on the wheel, it goes back to the 993 days when the early cars only had the tiptronic control via the gearstick.

Tim can you call me on 07710-960 695 and I can explain, I dont want to post details here for a week or so but please call me.

Regards
Paul

 

[MikeO]

Finally got to try it today with the new air mass sensor; I think it's sorted the problem []. Taking it down to Brighton for a few days so will get a few good runs, but so far it seems much smoother - can never be sure with intermitent problems - time will tell.

 

[ArBee]

Mike,

It is six months of protection under the Sale of Goods Act in which the burden is on the dealer to prove the vehicle is fit for the use it was sold to you for and they, the dealer, has to either take back the vehicle or you can demand that the vehicle is repaired.

Check out this link on the autotrader website http://www.autotrader.co.uk/CARS/buy/ba/ba-8.jsp

ORIGINAL: GreigM

Mike - regardless if you got a warranty or not - if you bought from ANY sort of car dealer you get a months full warranty - law I believe, so get them to sort it pronto.

 

[TISPKJ]

It gets better, the car went in last week Thursday and Friday, had a call from the service Manager to say all done and the car now goes like a rocket !!
Finished work early picked the car up and pulling away from the dealership you could tell that the car was still not right, floored it to find the car would not pull beyond 4000 rpm, called the dealer to ask if they had done anything to the car as it was the same as it went in !!
Took car in again today to find that the other variocam sender had failed on the other bank of cylinders, not in stock so have to wait another day for parts see what happens next ..........

 

[MikeO]

What a saga! Hope it gets sorted.

Mine seems basically sorted although I still think it stutters sometimes. It also seems inconsistent, sometimes pulling better than others. Fed up with it now though, I'll take it back if it worsens, cos I suspect I'm just been neurotic now.

Got booked in for a trackday at Silverstone soon, so that hopefully will give a chance to test it against other 996s -- although I'm afraid everyone will be storming past me whatever.

I have noticed that having now had it a couple months, it doesn't seem quick anymore, I've even been checking in gear acceleration times against road tests to reassure myself, but basically , despite the above, it seems in the right ball park, I guess you just acclimatise. Maybe I need to drive something "normal" to remind myself what that feels like, bloody slow probably.

Hope it's not the beginning of a slippery slope - performance mods, GT3, Turbo, looking for that "oh my God ' feeling to come back.

Still gives a major buzz round the bends though, the only limit is my courage - I guess Silverstone should be awesome.

 

[TISPKJ]

Well they have had it 4 days so far ..........

Theve now managed to stap off three of the exhaust manifold studs, can happen I suppose but now we need an engineering firm to remove them !

Should be back tuesday, another missed weekend.

Sooner those SL55 prices drop the better ........................

Will let you know
Paul

 

[lee fulford]

Tispkj

You wouldn't want an SL55, too must power for you 996 boys...oh and then there's the quality and equipement......nappa leather comfort massaging and air conditioned seats etc......

lee

Anyway I told you..get shot of the unreliable old nail and treat yourself to an appreciating asset...993 or a 964 RS...(blimey I sound like Des)