2006 159 JTDM 2.4 stalling / rough rev's / limp mode

[Hollylouise]

I own a good looking but dodgy running Alfa 159! I have recently had it serviced in the hopes a tune up would help my issues. They have got slightly better (eg- not dropping close to stalling or actually stalling without rev's or constantly going into limp mode) BUT now the rev's actually jump up on idol and it sounds like I'm sitting there flicking the throttle and when driving slow (eg in a school zone) it actually makes the car jump forward (which not only looks and sounds stupid but is a bit on the dangerous side). It happens on and off (I used to think it was in time with the AC cutting in but now I'm not sure) and runs like a tractor when first starting up. I've had the car for almost 4yrs and in the beginning I loved it to bits but now it's really getting on my nerves as no one seems to be able to tell me (or fix) the issue. I have heard it could be the EGR valve or a lambda sensor or possibly a MAF sensor but don't have much knowledge of them. I would appreciate opinions if you have had a similar / same issue and managed to fix it!! And also places on the Gold Coast to get this done as I find Alfa themselves extremely expensive and not all that friendly / helpful and other places not trustworthy. Thanks in advance 

[Mick A]

Sorry to burst your bubble, but you are going to have to spend money on your car to fix it.

I'll cut and paste my last response to your same question in another section of the forum here for you and others to read again, because it is likely it's going to be correct.

Hi Hollylouise,

Obviously I can't see the car, so I can only make an educated guess. The symptoms you describe are typical of worn bushes on the intake manifold swirl flaps. They allow pressure to escape the manifold causing inconsistent idling, and sometimes a loss of power depending on how bad this is in conjunction with a buildup of sludge and soot inside the manifold.

On the manifold there is a rod which links all five swirl flaps, and there is an actuator underneath the manifold which is attached to number five swirl flap, this single swirl flap bears the weight and operates the other four swirl flaps via the linkage, as this puts extra pressure on number five it wears the bushes out quicker and causes the leakage. You will see soot around the top of the inlet manifold behind cylinder five if this is the case.

The only worthwhile fix for this in my opinion is to replace the inlet manifold completely. It is a Peirburg unit, and readily available from numerous sources in the UK for half the price of one from Alfa Romeo Australia.

I work at one of the independent workshops in Melbourne which Colin has referred to in his post, and I have replaced quite a few of these now and it is absolutely worthwhile doing if you have a car that is over 140,000km old. It is quite a big job and involves removing the cam belt and high pressure diesel pump, so it is a good idea to tie it in with a cam belt and water pump interval.
We also install a restricting plate in the EGR valve along with a proper clean of the EGR, which involves dismantling the valve assembly and also the solenoid to clean the pin which operates the valve.

To remove and replace the manifold, cam belt, water pump, and bleed the system etc, you may be looking at anywhere from say 10 to maybe 16 hours labour, depending on the workshop and their experience with this job.
Then you have parts on top of that, so if this ends up being the problem you should expect to part with a couple thousand dollars.

Once again I cannot see your car, so all this is still an educated guess based on what you have described on this forum.

Cheers.

Mick.