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Discussion Starter #1
I own a 2010 93 1.8t auto which has Maptun stage 1 (220bhp) software on it.

I have been trying to rectify the performance issue I have with the car for years now, but as yet no luck.

The engine has a slightly rough idle and will sometimes feel like it is losing power or pulsing when accelerating hard. It feels like it is misfiring or being held back by something.

So far I have replaced the spark plugs, the coils, the boost control valve, the MAP sensor and have cleaned the MAF sensor, but the problem is still there. It has also been to a Saab specialist a number of times and still no joy.

Does anyone have any suggestions ? as I am now thinking it may be the throttle body, but don't really want to spend anymore money without being sure.
 

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1. Confirm coils have saab and mitsubishi stamped on them.
2. oil in spark plug valley?
3. spark plug brand and model?
4. check for vacuum leaks
 

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Discussion Starter #3
I had all four of the new coils fitted at Saabtech on the same day and it made no difference, but I will check them.

I will check the spark plug valleys and get back with the brand and code.

Where do you suspect a vacuum leak could be from and how would it be checked ?

Sorry to be a pain, but it is really bugging me that I can't locate the issue as I have done so much work on cars in the past and always managed to sort things out.
 

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Check the lines off the T valve near the oil dipstick.
 

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Discussion Starter #5
Thanks very much for that. I will check all of the items you have raised at the weekend and get back to you.

Cheers !!
 

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Discussion Starter #6
Hello Diggs,

I managed to check the items you raised last night, as I decided to replace the crankshaft position sensor, so did it all in one hit. Answers to your queries are as follows:-

1) The coils do have both Saab and Mitsibishi stamped on them.
2) The spark plug valleys are completely clean.
3) The spark plugs are NGK R PFR6D 10G. I could not find my feeler gauge, but they looked like they were gapped at 1mm. What I did notice was that although the electrodes were clean the bottom flange of all of the plugs was blacker with carbon deposits than any other other plug I have ever seen. This may be because my journey to work is only 11 miles and I never push the car until it is fully warmed up.
4) I cannot see any problems with the pipes coming off the T valve so don't think there is an issue there.

It is too early to say if the new crank sensor has fixed the problem although I suspect not, as I did a quick test last night and at about 1/3 throttle it felt like the car was trying to decide wheather or not to hold boost so that slight surging feeling was there momentarily.

I wonder if a temperature sensor could be playing up, so the ECU thinks the car is too cool on occasion or if a different plug may help as I generally drive the car quite sensibly, which may be allowing them to get fouled.

Your input is very much appreciated and anything else you can suggest would be very helpful as I don't just want to give on the car.


Regards

Daniel
 

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Were the coils used or new?

I wonder what the D in the plugs stands for? OEM should be NGK PFR6T-10G
 

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Discussion Starter #8
The coils were brand new. As for the code on the plug I am not sure, though for my car, which is a 2010 Parts for Saabs do list them for my engine and they were fitted by a Saab approved garage.

Maybe I should try another plug type as the remap may be upsetting them.
 

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Try NGK BCPR7ES plugs. Gap to 0.9mm.
 

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Discussion Starter #10
Thanks for that suggestion, as soon as I have sent this I will order a set.

I will post the outcome once I have had given the car a proper road test.

Cheers !
 

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Discussion Starter #11
Hi Diggs,

As I suspected changing the crank position sensor had not fixed the problem. A couple of days ago I was at about 1/3rd throttle, going up a slight incline and the car bucked again, so last night I managed to get time to change the plugs.

I have taken the car out twice since and it does appear to like the plugs you suggested. I keep trying to replicate the situation most likely to upset it and so far no bucking.

I have also purchased some thottle body cleaner and a new gasket, so will hopefully get a bit of time over the next week or so to get that cleaned up.

Fingers crossed though the car definately feels better with the new plugs.

I will update you again when I have put a few more miles on it.
 

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Discussion Starter #12
Diggs,

You have fixed my car !!!

After two and a half years, numerous visits to Saab and the replacement of hundreds of pounds worth of parts my car is now fixed.

It feels stronger right through the rev range, especially low down, is smoother and generally much more willing.

I have not had a single episode of the car bucking or missing and am now confident that it is running as it should.

I held off from cleaning the throttle body until I was sure that the new plugs had cured the issue. Now that I am, I am going to clean it up and replace the gasket this evening.

I am genuinely very grateful that you took the time to help me.

Thanks very much !!
 

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You're welcome. Glad to hear it got sorted.
 

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FYI, You'll need to change those plugs in about 10k miles/15 km. Good thing they are pretty cheap.
 

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Discussion Starter #15
Luckily I only do about 8,000 miles a year, so well worth replacing them regularly and having the car work properly.

I have gone from putting up with my 93 to enjoying it again and will certainly be letting the Saab garage know what finally fixed it.
 
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