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Robert, UK Qualified Car Technician
Category: Car
Satisfied Customers: 4708
Experience:  Fully qualified / self employed garage technician in the UK
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My Saab 93 (06 plate) Diesel automatic suddenly loses power

Customer Question

My Saab 93 (06 plate) Diesel automatic suddenly loses power and drops down a couple of gears. It then won't go above 55 mph. After a while if the road then dips downhill it suddenly goes up a couple of gears and shoots off.
Submitted: 1 year ago.
Category: Car
Expert:  Robert replied 1 year ago.


Are there any warning lights come up when this fault occurs at any point?

Any unusual noises from the engine or any problems regarding the gearbox at anytime?

What things have been checked or replaced so far upto this point

Customer: replied 1 year ago.
The engine management light came on but this is nothing unusual - it tends to come on and stay on for no apparent reason (for 3 years now). The 'waste gate' has been cleaned and checked, which usually does the trick. No unusual noises or problems with the gearbox. Speaking to other Saab owners this loss of power seems to be a common fault but nobody seems to know what the fundamental problem is.
Expert:  Robert replied 1 year ago.

Ok...Well the engine management is likely something that needs to be interogated at least to see what fault codes either history or pending or current is stored so that would be one thing to address first..i note you mention the turbo waste gate being cleaned..i cant see how they could do that as the turbo on these engines which is pretty tight to get to added to that the waste gate on the turbo is vaccum if the waste gate on that is sticking then its likely the VNT mechanisim stuck with carbon inside the turbo exhaust housing.....One of things thats quite common on these is the inlet swirl flaps and the egr passages/thottle body falp becoming blocked or stuck with carbon build up..and this can cause a power issue aswell as set various EGR /Flow fault codes...This is all on the understanding that the DPF diesel particulate filter on the exhaust is not partially blocked..they can check the saturation percentage levels on diagnostics and force regen if required..but as above id maybe be lookcing at the swirl flaps especially so the rod that actuates the flaps isnt broken and moves..aswell as ensure the egr valve is clean and the passages within the inlet manifold are clear..they may have to remove it to do all those checks..I do hope this helps

Customer: replied 1 year ago.
Thank you for the information - I will get my mechanic to check it out. I have two Saabs, this one and a manual 95 which both have the same type of problem. Also almost every Saab owner I speak to experiences similar loss of power. My old Saabs never had this problem so I guess it is something to do with the Vauxhall engines - although Vauxhalls themselves do not seem to have the problem. We will keep investigating
Expert:  Robert replied 1 year ago.

Yes they are basically a Vauxhall Vectra C base these saabs and use the same diesel engines..and they too can often produce the same syptoms..and normally 9 times out of 10..its usually one of those components or areas above..on the diesel 16v 150 engine..the swirl flaps are a very common problem they need to be freed up or jammed in the open position without any problems to the engine.done it many times on both saab and vauxhalls..the 120 8v is the better engine with really only the egr giving trouble...But yep have them check out all the above and see if solves you issue...But before you log out please dont forget to rate my answer..much appreciated