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Discussion Starter #1
Almost 80K on my 2.8T Combi and began having a stumble under heavy load out of 4th or 5th, no cels. Occasional for about 2 weeks. Based on research, ordered 3 coils (STI) and plugs (NGK PLFR6C10G). When I fueled up, I added some injector cleaner and tried it again. Mistakenly, I reved it to redline a few times hoping to clear things out and it stumbled badly at one point and the cel flashed, then went out. Stayed out but ran rough the 10 mi home. Scanned it and no codes present or pending, nothing in freeze frame. Replaced the 3 rear coils and all plugs (left them at 0.040). Fixed the check valve I busted (JB weld and outer hose).
Test drove it and it ran strong for about 5 mi after warmup when I was pushing it and then it misfired again and ran rough. No cel. Drove it gently a while and it cleared up. Pushed it a little and it seemed OK didn't push it. Idle was smooth. Parked it and then drove it about 2 hrs later. Cel came on almost immediately, flashing then steady. Barely began to drive. Had to complete the drive (about 20mi) and it was very rough and no power around 2500 and very rough. Somewhat better around 3500 and I made it home. Clearly one or more cylinders not running right, idle was lousy. Code P0305, Cyl 5 misfire. Swapped the 3 front coils for the ones pulled from the rear and no change (none really expected but worth a try). I'm certain everything was re-assembled properly, of course it's #5.

So.....Time for an injector on #5 or should I be looking elsewhere? I really don't want to replace the set. Can the Bosch "Green Giant" 9202100 be used or should I stick w/ a SAAB OE part? Pricy buggers.
It's a pain to pull the plugs again to re-gap but if there's a strong reason to do that, I will.
Any suggestions would be a help, I'd struggle to get a capable shop to look at it, I'm sure it would be huge $$.
 

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Pull #5 again and check the plug, make sure there's no oil in the port, inspect the coil connector for melting and also the wiring to the coil. Also make sure there are no other broken plastic vacuum hoses.
 

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Pretty sure this is the numbering system as well:

Firewall___________
1 3 5
2 4 6 [bat]
Front ____________

So messing with the the front 3 isn't going to solve P0305.
 

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Discussion Starter #5
Thanks, yeah #5 is the most fun to get to.:( I'm going to go ahead w/ the injector (stock one) for #5. It will be here tomorrow and shouldn't be too bad to do. If that doesn't do it, I'll get into the rear bank again and do what you suggested, probably regap all to 0.035 or 036 and do a full compression check. It will be cold by the time I can do it but it should show me if something is badly hosed.
 

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Hey Dr. Saab.

Let me know how this turns out for you. I'm having the same issues (07 9-3 aero, vtuned stage 0). The car was sitting for a year and a half. I topped it off with 93 octane and some seafoam. Still getting misfires if I would push it around 3/4 throttle.

New Denso plugs that Vtuner recommended (gaped to .85mm) and all new Bosch plugs. Still misfired, but, was still running on that old gasoline. I just topped off with injector cleaner, octane booster and 93. It seemed to run a bit better, but I still felt misfires every now and then. Didn't push it past 3/4. I plan on doing two tanks of 93/injector cleaner/octane booster followed with one final treatment of seafoam. If that doesn't clean it out, I may go get it looked at.

It wouldn't throw a code unless I would keep on the gas while it would misfire, then go put put put. Codes were random misfire P0300, and cylinder 5 - P0305. Before changing plugs/coils the misfire was on Cyl3. Now it has jumped to 5 (I think it was cyl 2 at one point also). Which is making me believe its just the gasoline.

If its still doing the misfire after 3 fill-ups I'll look into replacing an injector.
 

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Discussion Starter #7
DR are initials, wish I was a SAAB Dr.!
Injector installed- No love, Compression check showed #6 down a little, 160 vs 175 for most others but #3 was 165 so nothing major broken or leaking, probably just oil wiped more from rings since cylinder isn't firing.
Still P0306, at least it posts and points to the right cylinder.
Doing research points to either coil or injector wiring or perhaps driver from ECU. Just downloaded WIS and will try to run it tomorrow.
If the wiring diagrams look sane, I may try diagnosing further.
The ***** is that to get to the coil or injector connectors, all the plumbing in back, ecu, manifold etc have to be moved. I was able to cobble cranking it while I had access for compression check but certainly won't be able to run it to monitor on a scope or anything.
I'm suspicious of the connector or wiring for the injector harness since it's right next to the turbo heat shield.
 

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Discussion Starter #8 (Edited)
Just got the call from the shop on my car (20 yr SAAB tech @ a local X SAAB dealer)- Bad new coil on #5.
I'd swapped 3 and 5 but they said they were not surprised it didn't track. Something about adjacent cylinders and how they are tracked. They moved it to #2 cleared the code and it re-posted on 2.
These were BREMI/STI coils so a vote against. I hope that fixes it....
Pick it up tonight
 

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For what its worth, I fixed the misfire on my v6 with fresh NGK spec plugs and the updated Bosch coils. Did all 6 and runs super smooth.
 
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