1st and 4th Cylinder misfire

The hcf delete and the kn filter had nothing to do with it. I would replace the the pcv valve and spark plugs and run some 93 in it and see what happens.
 
Huh... I'm trying to think what you could have done that would have set the vehicle over the edge like that... Do you have access to a scantool that can get Datalist information?

I'm wondering if all that chemical treatment knock some sludge loose that found its way into the pcv valve.
 
I'm wondering if all that chemical treatment knock some sludge loose that found its way into the pcv valve.



Ive got the same issue and am about to replace the pcv after class tonight. Will update with results tomorrow


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FmL!
So codes on cylinder 5 and 6 now...also c1201 Now. What next

Lol


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Take the coils from 5 and 6 and move them to the opposite side of the motor, clear the codes, drive till check engine comes back and check again and see if the codes moved to the cylinder that you just moved the coils too


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Yoda is BACK!!

Thank you BlackWorksInc, TrueBlue, Morphyne, and everyone else who chimed in to help...

I replaced all plugs with Denso's, added a little dielectric grease to coil connections and boots, pulled the PCV (nasty) and cleaned it out. Had the battery disco'd whilst working...about 2 hours total including all the interruptions and misplacement of tools :) ....

Put everything back together and fired it up. Let it idle for a good 5 or 10 minutes. Took off on a little West Texas night time road trip to test out this fix.

She never missed a beat. Runs like new...the old plugs were completely shot, mostly worn away, and ash colored - super fouled. Should have just replaced them from the get go...live an learn I guess.

And that's why I joined this forum, for insight from people like you who have been there/done that...and are willing to help newbies like myself! Truly awesome....

I really appreciate all of the help. Great forum with some great people.


PS - if something goes haywire in the next few days, I will post back, but as of right now I am pretty sure Yoda is good to go!

Stay Classy...


Hoop
 
Thank you BlackWorksInc, TrueBlue, Morphyne, and everyone else who chimed in to help...



I replaced all plugs with Denso's, added a little dielectric grease to coil connections and boots, pulled the PCV (nasty) and cleaned it out. Had the battery disco'd whilst working...about 2 hours total including all the interruptions and misplacement of tools :) ....



Put everything back together and fired it up. Let it idle for a good 5 or 10 minutes. Took off on a little West Texas night time road trip to test out this fix.



She never missed a beat. Runs like new...the old plugs were completely shot, mostly worn away, and ash colored - super fouled. Should have just replaced them from the get go...live an learn I guess.



And that's why I joined this forum, for insight from people like you who have been there/done that...and are willing to help newbies like myself! Truly awesome....



I really appreciate all of the help. Great forum with some great people.





PS - if something goes haywire in the next few days, I will post back, but as of right now I am pretty sure Yoda is good to go!



Stay Classy...





Hoop



Glad we could help you out. I'm no expert myself I've just been researching this topic trying to figure it out myself since i have the same issue, do let us know if anything goes wrong I'll be glad to try and help you out with anything else. Have a good one man hopefully it stays pristine (prestine?) for many more years. Cheers


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Glad we could help you out. I'm no expert myself I've just been researching this topic trying to figure it out myself since i have the same issue, do let us know if anything goes wrong I'll be glad to try and help you out with anything else. Have a good one man hopefully it stays pristine (prestine?) for many more years. Cheers


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Do you have a thread going on your issue?? Would love to know how things go...


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Do you have a thread going on your issue?? Would love to know how things go...


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Nope but I'll respond back in here I guess since it's sort of the same topic. If you don't mind that is


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Nope but I'll respond back in here I guess since it's sort of the same topic. If you don't mind that is


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Oh not at all please do... permission to semi-hijack granted... Lol.


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So since I was given permission to Threadjack for a bit I guess I'll give a little backstory to my problem and how I'm going about it. I'm gonna do things in order of price to give any other readers sort of a checklist to run through so you don't have to break the bank. I have an 06 Limited AWD V8 with 317k on odometer. Recently I've run into the issue of rough idle at OP. temperature and random occurrences of hiccuping while driving, all of this along with noticeable power loss. I threw the same code for Cylinder misfire on 2 and 6.

Step 1: Disconnect the battery for about 15-30 minutes and reconnect it. I always do this step first because you never know if your computer is just having a hissy fit. Cost = $0

Step 2: Clean the MAF sensor and throttle body and disconnect the battery for another 15-30 minutes. This step is pretty crucial if you have installed an oiled air filter and if you've done the popular HCF Delete. Cost = ~$8-$10

Step 3: Check and clean the PCV Valve. When the PCV gets all gunked up it can cause the rough idle symptoms. Not too sure if itll cause the hiccuping I'm getting though. Cost: ~$10 to replace, ~$3 to clean or none if you reuse the throttle body cleaner from the previous step.

I've done all these steps and I'm still experiencing my symptoms. Next step would be to replace the plugs in those cylinders or all of them, however my set of plugs if really new, around 500 miles on em, so I didn't need to do this step. I did however pull the plugs to check if they're in bad condition, which they were not. For good measure I went ahead and replaced em, symptoms persisted.

Step 4: Replace ignition coils with OE Denso coils in bad cylinders. I'm currently waiting on my coils to ship in so I can't report if this fixed my problem. It's highly recommended to use the OE coils in our trucks because they act funny with other coils, as you'll notice if you read earlier in this thread.

That's all I got as of now. Will report back later this week when I get the coils.



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So since I was given permission to Threadjack for a bit I guess I'll give a little backstory to my problem and how I'm going about it. I'm gonna do things in order of price to give any other readers sort of a checklist to run through so you don't have to break the bank. I have an 06 Limited AWD V8 with 317k on odometer. Recently I've run into the issue of rough idle at OP. temperature and random occurrences of hiccuping while driving, all of this along with noticeable power loss. I threw the same code for Cylinder misfire on 2 and 6.

Step 1: Disconnect the battery for about 15-30 minutes and reconnect it. I always do this step first because you never know if your computer is just having a hissy fit. Cost = $0

Step 2: Clean the MAF sensor and throttle body and disconnect the battery for another 15-30 minutes. This step is pretty crucial if you have installed an oiled air filter and if you've done the popular HCF Delete. Cost = ~$8-$10

Step 3: Check and clean the PCV Valve. When the PCV gets all gunked up it can cause the rough idle symptoms. Not too sure if itll cause the hiccuping I'm getting though. Cost: ~$10 to replace, ~$3 to clean or none if you reuse the throttle body cleaner from the previous step.

I've done all these steps and I'm still experiencing my symptoms. Next step would be to replace the plugs in those cylinders or all of them, however my set of plugs if really new, around 500 miles on em, so I didn't need to do this step. I did however pull the plugs to check if they're in bad condition, which they were not. For good measure I went ahead and replaced em, symptoms persisted.

Step 4: Replace ignition coils with OE Denso coils in bad cylinders. I'm currently waiting on my coils to ship in so I can't report if this fixed my problem. It's highly recommended to use the OE coils in our trucks because they act funny with other coils, as you'll notice if you read earlier in this thread.

That's all I got as of now. Will report back later this week when I get the coils.



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That's a nice write up. I'll take note of this the next time. Makes things flow and it is easier to understand. BTW, picked up some OE Densos on Amazon for a lower cost than I could find them locally. Free shipping as well with Prime.


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That's a nice write up. I'll take note of this the next time. Makes things flow and it is easier to understand. BTW, picked up some OE Densos on Amazon for a lower cost than I could find them locally. Free shipping as well with Prime.


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Thanks, and that's exactly where I got mine from lol, I think they came out around $57 each if I recall


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So since I was given permission to Threadjack for a bit I guess I'll give a little backstory to my problem and how I'm going about it. I'm gonna do things in order of price to give any other readers sort of a checklist to run through so you don't have to break the bank. I have an 06 Limited AWD V8 with 317k on odometer. Recently I've run into the issue of rough idle at OP. temperature and random occurrences of hiccuping while driving, all of this along with noticeable power loss. I threw the same code for Cylinder misfire on 2 and 6.

Step 1: Disconnect the battery for about 15-30 minutes and reconnect it. I always do this step first because you never know if your computer is just having a hissy fit. Cost = $0

Step 2: Clean the MAF sensor and throttle body and disconnect the battery for another 15-30 minutes. This step is pretty crucial if you have installed an oiled air filter and if you've done the popular HCF Delete. Cost = ~$8-$10

Step 3: Check and clean the PCV Valve. When the PCV gets all gunked up it can cause the rough idle symptoms. Not too sure if itll cause the hiccuping I'm getting though. Cost: ~$10 to replace, ~$3 to clean or none if you reuse the throttle body cleaner from the previous step.

I've done all these steps and I'm still experiencing my symptoms. Next step would be to replace the plugs in those cylinders or all of them, however my set of plugs if really new, around 500 miles on em, so I didn't need to do this step. I did however pull the plugs to check if they're in bad condition, which they were not. For good measure I went ahead and replaced em, symptoms persisted.

Step 4: Replace ignition coils with OE Denso coils in bad cylinders. I'm currently waiting on my coils to ship in so I can't report if this fixed my problem. It's highly recommended to use the OE coils in our trucks because they act funny with other coils, as you'll notice if you read earlier in this thread.

That's all I got as of now. Will report back later this week when I get the coils.



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I would pull the plugs and check their condition and also their gapping and make sure they are actually the right ones for your engine. some times you can get a couple of goofy plugs mixed in with the new ones. or they can be bad form the factory, it happens. You didn't say you replaced the plugs as part of the fixes on the misfire but they only have 500 miles on them. I am going to put my wager over there....

Edit: I reread your post. you have already done this. Back to the drawing board....

Bad gas?
 
Last edited:
I would pull the plugs and check their condition and also their gapping and make sure they are actually the right ones for your engine. some times you can get a couple of goofy plugs mixed in with the new ones. or they can be bad form the factory, it happens. You didn't say you replaced the plugs as part of the fixes on the misfire but they only have 500 miles on them. I am going to put my wager over there....



Edit: I reread your post. you have already done this. Back to the drawing board....



Bad gas?



Fresh tank of 91 from Chevron. Did this specifically to see if it'd combat the misfire. I'm highly positive it's the coils as they're the factory coils with 317k on them. But we'll see. The coils should be here tomorrow


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If the coils don't work, may be time to check your injectors, but we will wait and see


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I understand that people haven't had/heard of coil failures with these engines but my Saab would go through coils (quality Bosch parts, very similar design) every 75k mi. Most of the time these coils would still produce a spark and the OBD would not throw a code, but a good data log would show elevated KR values for the cylinder in question. Symptoms were cold start hesitation, decreased fuel economy, etc. I would basically replace plugs and coils at a 75k interval on that car. Your symptoms sound similar to failing/weak coils to me. The primary culprits are typically the ones closest to the firewall, presumably due to the higher temperature levels. Apples to oranges here I know, but I thought it was worth chiming in.
 

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