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Discussion Starter · #3 ·
Sorry yes it is, it's an auto and I have the right plugs in it these BCPR7ES-11.
I dont understand it if your sitting at light's ect in drive it's fine, but as soon as you put it in nuetral or park it starts missing.
 

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I would guess that while in drive their is a +ve load on the engine and it is having to do some work to keep at idle.

In neutral the engine has no load and i'm guessing is using less air and less fuel, which may lead to a harder to ignite charge.

Andrew
 

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Mine ran way better after cleaning the throttle body and more importantly the AIC valve:

http://www.saab9000.com/procedures/fuel/iac.html

I think the IAC valve only operates at a pure idle (i.e. with main butterfly closed).
When you put the car into drive there is a loading on the engine and it needs a bit of throttle to keep it running at the same rpm and seems enough to sort out the fueling/mixture.

Well thats my theory anyway.

fyi - After cleaning the AIC valve, car starts with a nice sweep of revs up to 1500 and back to a very smooth 800 or so. Previously it would fluctuate and judder unless you gave it a little bit of throttle.
 

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I'm pretty sure this has been discussed before - I certainly remember posting something about it once and I think the answer was that a slightly lumpy idle on a 2.3FPT was just one of those things. Certainly mine does it and the only thing I've found that does reduce it is regular doses of Injector Cleaner.. which I suspect has something to do with the volatile fragments in it just allowing for a slighly smoother burn.
 

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Originally posted by JohnCC:
[qb]I've been told by at least two indies now that a slightly lumpy idle is normal on these cars.

*shrug* [/qb][/b]
Especially if it's had a headgasket job and they have refitted the tinming chain 1 tooth out on 1 of the cams....

That also give lumpy power low down but clears above about 2000rpm.

Andrew
 

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On mine I've replaced the HG and timing chain, had the injectors cleaned and replaced the DI and plugs, and the idle is still not spot on.

It's not that the power is lumpy - it's just that if you leave it ticking over, you can hear it stumble every now and then.

One of them told me that it is because they idle very lean... not sure if there is any truth in that!

I think they were probably telling me not to be such a perfectionist, in the nicest possible way
 
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