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Ok. Just read about the idle relearn. Did something like that when the TB was changed. No difference. Not sure if that would affect misfires though. Think it would?
 

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94 octane fuel should not clog injectors. I'm leaning towards those coils and plugs like originally stated. The coils got worst when you rotated them around or no difference at all. If you put newer plugs in and still no change what so ever then you should be looking at the coils. Your symptoms are pointing at the ignition system. It would be a 1st for me not to see any codes but the car is misfiring and hesitation.
 
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You’re right. Misfiring and hesitation from idle. Next up is changing plugs and go from there. After that if it doesn’t cure it I’ll have to wrestle out the injectors and clean them. I’ve borrowed a hand held cleaning kit so that’s good. If they weren’t such a huge pain to get out from the Edelbrock blower I would have done it already.

One thing at a time and hope for the best...
 

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Ok. Just read about the idle relearn. Did something like that when the TB was changed. No difference. Not sure if that would affect misfires though. Think it would?
It stopped mine from ramping up fast. I'll have to find the video I had of watching them go up on my monitor. All cylinders would creep up in the hundreds at idle. I was able to get it to tame down with a crank relearn and idle relean,, but never eliminated it.
Like I said, somewhere between changing the vct solenoids, complete timing kit, new battery and new injectors when installing the whipple pretty much fixed it.
 

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It stopped mine from ramping up fast. I'll have to find the video I had of watching them go up on my monitor. All cylinders would creep up in the hundreds at idle. I was able to get it to tame down with a crank relearn and idle relean,, but never eliminated it.
Like I said, somewhere between changing the vct solenoids, complete timing kit, new battery and new injectors when installing the whipple pretty much fixed it.
Yes. Find the video! I’d like to see it.

Thank you!
 
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Nope. Not of as yet. New plugs should get here tomorrow. Then maybe do the injectors next week if the plugs don’t cure it.
 
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Just got a chance to change plugs this morning. Haven’t had a chance to drive or start it yet.

Couple of pics. Interesting - the #1 and #5 appear a little darker and “wettish” than the others.

Have a look and let me know your thoughts on what may have caused that. Car was driven about 700km since pics of the plugs last time. Babied for these miles - long easy tour on the weekend.

Thanks

19EAF3AF-78D9-4061-929B-7CC8A1A1C772.webp


20219887-36E7-4930-9E83-74F9EBAEFD28.webp


5F599FF2-426C-40AC-B543-9CE0037E44D0.webp
 

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Just got a chance to change plugs this morning. Haven’t had a chance to drive or start it yet.

Couple of pics. Interesting - the #1 and #5 appear a little darker and “wettish” than the others.

Have a look and let me know your thoughts on what may have caused that. Car was driven about 700km since pics of the plugs last time. Babied for these miles - long easy tour on the weekend.

Thanks

19EAF3AF-78D9-4061-929B-7CC8A1A1C772.webp


20219887-36E7-4930-9E83-74F9EBAEFD28.webp


5F599FF2-426C-40AC-B543-9CE0037E44D0.webp
Fouled plugs that are wet points to ignition coil system that isn't firing properly. Those 2 plugs could indeed be the trouble cylinders of the coils. If the new spark plugs doesn't eliminate the misfires then it's your coils as suspected
 

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Plugs aren’t wet per se. Shiny bottom and a little shiny ground strap. Insulator and electrode are same as the others. Can’t wipe anything and no wetness with a Kleenex. The other 6 plugs are basically identical. The 2 odd balls are 1 and 5 - both at the front of the engine for what that’s worth. All gaps checked in at 28 after removing.

Hopefully the new plugs correct everything. If not, perhaps coils. Would it be odd for 2 coils to go out at the same time?

Haven’t cleaned the injectors yet. Keep putting that off as the fuel AFRs in the logs don’t point to a fuel issue. But it could be I guess. I did run Royal Purple injector cleaner through it in the hopes it would make some difference but no luck.
 

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Plugs aren’t wet per se. Shiny bottom and a little shiny ground strap. Insulator and electrode are same as the others. Can’t wipe anything and no wetness with a Kleenex. The other 6 plugs are basically identical. The 2 odd balls are 1 and 5 - both at the front of the engine for what that’s worth. All gaps checked in at 28 after removing.

Hopefully the new plugs correct everything. If not, perhaps coils. Would it be odd for 2 coils to go out at the same time?

Haven’t cleaned the injectors yet. Keep putting that off as the fuel AFRs in the logs don’t point to a fuel issue. But it could be I guess. I did run Royal Purple injector cleaner through it in the hopes it would make some difference but no luck.
2 coils bad at the same time isn't uncommon lol. I think that’s the only thing that haven't been officially changed. That's the bad part with the s550 coils. It will start your vehicle as should but it may not function 100% as it should. And it's no real definitive way of checking coils besides switching cylinders which you have done with no improvement. Did the new plugs help by chance?
 

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I would try getting new coils or trying to borrow someones to test.

Even if it doesn't help you can at least rule it out. I think you have ruled out vacuum. Since the car runs I think it's safe we can rule out air. You only really have spark plugs and coils for the ignition system. So try to eliminate ignition. If swapping new coils doesn't help then clean injectors, check fuel pump. If fueling also doesn't seem to be the issue then you will need to check the wiring.
 
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I hear you. Running out of things to try. Went in with the mindset of not just throwing parts at it but it’s kind of looking like it’s going that way.
 

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I hear you. Running out of things to try. Went in with the mindset of not just throwing parts at it but it’s kind of looking like it’s going that way.
What is tricky is if it truly is multiple cylinder misfire and multiple coil packs are bad then you can’t really easily swap to find out.

Maybe keep swapping and see if you can find a pattern idk.
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