GREAT!!!!! Now, what I would do is to use a digital multimeter (or if you have one an old fashioned analog ohm meter - even better in my opinion) to check the resistance of the bank 2 spark plug wires. The typical resistance of a spark plug wire is between 10,000 and 12,000 ohms per foot. Also, while the DMM or analog ohm meter leads are connected to a spark plug wire, wiggle the wire and watch the meter display for any sudden resistance changes. Sudden changes indicate a bad plug wire due to internal separation of the conductive material or a bad wire to connector crimp connection.

Checking the ignition coils is going to be tough because there is not a simple primary winding and a simple secondary winding that one can put a meter across to check resistance. There is a procedure that is written up in the Haynes Manual (Chapter 5 Section 6 {in my copy} that I would follow.

Also, visually inspect the spark plugs.

If you find that the spark plug wires are flaky, be sure an replace them with a quality replacement set such as ACDelco, Standard Motor Products/BWD, or NAPA Echlin. I've never had problems with any of those brands. Carquest by Prestolite (Advance Auto Parts) and Delphi are good too. Same thing goes with the coils - get ACDelco, Delphi, Standard Motor Products/BWD, or NAPA Echlin (just do not purchase the SMP T line or BWD P line parts, they are a lower tier, lower cost product aimed at low end repairs). Just as an FYI, Standard Motor Products manufactures and sells essentially identical (except for color) parts under the SMP and BWD names, and they also manufacture the Echlin line for NAPA (same parts as SMP/BWD).

If you wind up having to replace the spark plugs, go only with the ACDelco OEM plugs or the equivalent NGK plugs {FYI, NGK manufactures the majority of the ACDelco plugs now}.

Again, good luck and keep up the great work!

 

Will do! The current plugs are AC Delco and pulling one from cyl 4 under visual inspection was good when I was in the process of replacing the filler neck. The gap could be off just a hair maybe but i didn't have a gap tool at home. I have one now though. I have never attempted gapping iridium plugs before, gonna be a challenge if they are out of spec though.

.040 is the correct gap I think.

I will check the wires ASAP and get back on that. However for the coils since they are hard to test like you said (which I will still attempt), should I just move a couple to bank 1 and see if the misfires move? Its weird to me that the coils could be an issue since all of bank 1 is ok. Would be a crazy coincidence though.

 

Iridium plugs come pre-gaped from the factory and generally do not need to be adjusted. The best way to check the gap is to use a "universal" type gap checker that looks like a silver dollar and has a continuous ramp from small to large with markings to show various gaps. Manufacturers do not recommend using the fixed wire type gap checkers because the iridium, platinum or other precious metal plating is extremely thin and can be rubbed off by the wire type gap checkers.

Go ahead and swap the coils from one side to the other. If the misfire counts change cylinders, then you have diagnosed a bad coil or coils.

Also, here is a link I go to periodically for diagnostic assistance - https://www.aa1car.com/ They have a great deal of good and practical information.

Again, good luck!

 

Sounds good!
I will move the coil packs over (easier than testing), test the wires as well as check all the plugs.

Not sure if you already sent me info for the Haynes manual already but I looked back and couldn't find it unless im blind. I don't think I need it anyways though since I wont be testing the coils.

I will get back with more info after testing and well see from there.

Thanks a ton again! You don't even know how much i appreciate the help!

 

You are quite welcome!

 

Okedoke, had some things come up over the weekend but just finished testing wires literally 10 mins ago lol.
Results:
1) All 8 wires are 1000 ohms and within 50 ohms of each other (1000 - 1050). I remember you said 10-12000 is normal, i read a little bit online and I think you may have had a typo because I haven't read anything of anyone having that high resistance, i could be wrong, but still im unsure if these are ok or not. Even moving the wire the resistance was steady.

2) Pulled all plugs. Gap for these AC Delco should be .040. All the plugs on bank 2 (the misfiring side) were .048 and surprisingly on bank 1 the gaps ranged from .048-.055 but that side never gave issues lol. Everything is gapped to spec now, after a 5 min quick drive I feel like the truck is worse misfiring wise but well see tomorrow. Yes everything is connected well.

3) I did this thinking it would help aid in figuring out what is the culprit. I moved the Coils and Wires for cylinders 3 and 5 with 4 and 6. I moved only the Coils from cylinders 1 and 7 with 2 and 8. Reason being i will watch misfire data when the truck acts up and see if the misfires moved at all and depending on what cylinder i may be able to find if the issue is wires or coil packs if thats whats goin on.

4) Lastly i came across a 2 hour video with a 200k mile truck being diagnosed with what i could find the most similar issue to mine. He found that reading graph data for the 02 sensors proved one to be faulty. I took the time to graph 02 sensor data for upstream and downstream bank 2 short term and what i find is no movement on the graph for the downstream sensor. However both downstream sensors read 99.2% for short term readings but i still decided to swap them, no change. Just weird how the readings are a solid 99.2% all the time, i cant remember them being something other than 99.2%. Have 2 vids to show before and after the swap. This was before messing with coils/wires and while running normally.

Thanks for taking the time to help again!

 

Spark plug wires are supposed to have 10,000 to 12,000 ohms per foot. Only having 1000 ohms doesn't sound quite right to me. I know that the resistance is supposed to assist in reducing radio frequency noise emitted by spark plugs (static in the radio - especially on the AM band), but I don't know if 1000 ohms is OK or not.

OK on the spark plug gaps. Just remember to only change one variable at a time - easier to keep track of what does and does not work.

I'll look at the videos tomorrow when I am fresher - been a long day at this end.

 

it is not ok for 100 ohms that sounds to low to me

 

Not saying anyone is wrong, im all for the wires being the issue but how come only bank 2 gave misfires intermittently while all 8 wires were within 50 ohms of each other? Just a thought but maybe these could be the issue.

 

I admit, I am perplexed as well.

Hectic day and did not get a chance to view your videos. However, I do have one question about the downstream O2 sensors. Any idea how old they are - in terms of both mileage and age? Also, if you know the history, what brand are they? Trying to decide if they need to be replaced (with either an OEM or Denso). I do know that O2 sensors can get lazy and not respond as they should.