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Discussion Starter · #1 ·
Crusing down the M5 this evening in 5th doing about 85 the engine stumbled enough to cause the gear lever to wobble... it did it again a few minutes later as I decellerated down the slip road.

engine has 93K on the clock and has had the 3.5K rpm hiccup for a while... should I costing up a new DI cart?

Steve
 

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yes it could be,but it could be something else.i have one that goes fine for 10 miles/cuts out/wait 5 mins runs ok for at least 20 miles.its yours for free if you want it/these di things are strange i dont think they all fail the same way/some cut out completely,some missfire then run ok/ive one of those as well if you want it,your best bet,if possible is to fit a known good one and see if it still happens.cause it could be amm./icv/temp.sensor e.t.c. best of luck(been there) zep.
 

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My 9000 suffers from the hicup problem when decelerating, as soon as the revs hit 1500rpm it sort of jerks like you describe yours, the gear lever moves along with the engine, this happens only briefly before it settles itself, I have asked various SAAB dealers about this and they cannot find a problem, they claim its to do with injectors switching off to prevent emissions.
Does this sound similar to your problem, try running the car in second gear, take your foot off the throttle and let the car slow without braking, watch your rev counter and see if the engine/gear lever jerks at around 1500 revs.
 

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Discussion Starter · #6 ·
The minor intermittent stumbling has now turned into major staggers at all engine speeds... it even misfires at idle now... So is this rapid decline typical of DI carts or have I got some other major problem?

There is some ticking coming from the injector side of the engine but that seems to be constant and not intermittent .. so it may not be relevant.

Also checked the DI cart - there is no oil leak but the bottoms of the units are grey in colour and covered in a dusty substance. Have not spun the plugs out but AFAIK they were new 10K ago.

[added this bit later] : Having been looking round some people have had this when using "cheap" fuel. Having run a couple of tanks of Optimax through before reverting to Tesco I am wondering if the car has "learned" to use Optimax and needs resetting now its running on Tesco standard unleaded... or maybe its a bad tank of fuel which considering I filled up yesterday is a bit of a co-incidence

Steve
 

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Discussion Starter · #7 ·
This evening whilst babysitting for my brother I spun out the sparkplugs.

They were the correct type (ie NGK Resistors) and the ends were a grey/brown colour BUT the gap seemed very wide .. about 1/16 inch (Only had an old imperial ruler to hand) which is way too big isnt it?. So I guess I should get some new plugs ..

So could a combination of bad plugs and iffy fuel from Tesco (like less that 95 RON) do all of this?

Steve
 

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Try closing the spark plug gap down to 1.0mm first to see if this helps, beats forking out for new plugs if it doesn't cure the problem. Bad plug gaps and low grade fuel certainly could affect performance, had a spate of car's breaking down round here a couple of months ago, Sainsbury's were revamping their petrol station and the builders allowed water to get into the fuel.

Neil
 

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Discussion Starter · #9 ·
Regapped the plugs but the central anodes look quite short and seem to be burned at an angle (i.e. aren't flat)

Started it this morning and it ran fine until the temp gauge got to its normal position then it started mis firing but not as bad as yesterday

Stopped at the services near brum to use the loo and when I started it was fine... went onto the motorway and accelerated upto 80 with not one misfire, then after about quarter of a mile it started misfiring gently again..

Arrrrgggggghhhhh
 

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Discussion Starter · #10 ·
OK I am now back at home having stopped to refill with good fuel.

If I stop the car for a few minutes and then restart it it runs fine for a few minutes before starting misfire again....

I am completely stumped!!!
 

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Discussion Starter · #12 ·
Well thanks to Pete who has loaned me a spare DI cart I can now confirm that it was at fault... not one misfire in 15 miles....and more power too

Thanks to everyone who gave advice.

Steve
 
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