Since I have seen the ground strap burned away or broken on plugs that have been in for awhile I'm still going to change them this weekend. I will run some seafoam through the gas to help break up the carbon deposits in the head and use some penetrating fluid in the spark plugs holes while the engine is still warm to try and help it from both ends. I've found that I'm the one in a million chance when it comes to anything and even though I'll have the extractor kit there with me I'd just assume not have to use it. 😒

 

I'll take a whack at that one.

FIRST, we must accept one premise. The PCM (computer) is breath takeingly fast and smart - and includes several 'self-preservation' routines in it's software. ei: power reduction and catalyst preservation Misfire fuel shutoff to mention a couple of pertinent ones here.

The engines design focused on delivering _maximum_ fuel efficiency and meeting emissions requirements while maintaining best power/torque delivery. To get there, IT RUNS VERY LEAN and needs to burn every last molecule of fuel that enters combustion chambers. Trying to accomplish that it uses several systems that need to work together and correctly. Cam retard (which ingests exhaust gasses - proportionally to amount of retard for EGR) to reduce emissions and increase low end torque. BUT that leans mixture AND lowers compression making mixture harder to ignite. So it also employees CMCV (charge motion control valve) to create 'swirl' in intake air at injector nozzle to better atomize incoming fuel/air mixture. It also uses higher voltage ignition COP's and uses 'tripple strike' spark strategy at lower RPM (Ie below ~ 2250 RPM). And the plug tip extends down into the combustion chamber --- intended to run VERY HOT - at combustion temperatures - (HIGH HEAT RANGE PLUG). Carbon build up that touches the plug tip conducts heat out of the plug into water jackets within heads, lowering plug tip temperature. /// higher temp results in higher voltage SPARK - thus a more powerful spark flame ///

The PCM software logically determines a misfire by monitoring for an 'expected' brief acceleration in crankshaft rotation speed corresponding to the spark command. If that rotational acceleration is below a certain threshold = misfire, Codes P030x. NOTE: the spark plug COULD HAVE FIRED. But PCM knows the mixture didn't detonate and THATs what's important. THIS is what increases probability for misfires P030x when cam timing system deteriorates and a timing job is approaching. /// This leads to many erroneously 'chase' misfires on the electrical side of the equation ///. HOWEVER, the PCM actually is smart enough to distinguish and report primary/secondary electrical issues separately as Codes P035x (primary/secondary circuit failure).

Something you said confirms you do in fact have misfires.

Any misfire dumps the unburned fresh air into the exhaust - where O2 senses its presence. Logic dictates it also contains unburned hydrocarbons. Above a certain threshold the PCM does two very important self preservation things that explains your above symptoms. It illuminates the CEL (flashing) indicating a catalyst damaging misfire condition, and ALTERNATELY Shuts OFF fuel INJECTORS on certain cylinders ((DRASTICALLY amplifying the SHUDDER feel)) in an effort to preserve the 'expensive' Catalytic Converter.

When you back off throttle and (as you say), 'let it compose itself' it shuts off the CEL and re-enables the fuel injectors. ///This leads many to mistake this issue as a transmission Torque Converter 'chatter' as @BadFish523 reported.

 

Wouldn't it just be easier to have a hamster in a cage that turns a crank that clicks a switch that fires the spark plugs that makes the truck go? 😂

 

hamsters can't function on 87 octane

 

Often times I think it mite (that's a dig at SCORGE!) be easier if they still used points and condenser on which we set dwell and spark plug wires that we could observe in the dark looking for arc overs. But as they say 'it is what it is', or is it "we got what we got".

 

My dad dealt with those more than I did, I always had the hei systems.

 

My two cents here, buy the Lisle extractor tool made for the broken spark plugs before starting the job. That way IF one breaks off, you don't have to wait days for the tool. There's several people with tips and tricks on how they remove them. When I did my '07 I got the engine warm, loosened then 1/4 turn and let them soak overnight in Liquid Wrench after running a heavy duty fuel/engine cleaner through it. The next day I put an impact on them and let it rip. Using this method I did break one off, and upon inspection it looked much older and had a different batch number than any other plug. I had to wait a few days without a truck for the tool to come in so I could get the broken bits out.

 

Ok so I've made it through the driver side, fortunately the ones I'm pulling out are the updated 515 plugs. Number 2 had about an inch of dirt and crud in the hole to where I couldn't see the hex nut on the spark plug. Saw a slight bit of oil in the rear driver side hole but nothing major I think. My new question is as I was tightening the screw that holds the coil in place it never seems to hold it down tight, like I can wiggle and turn the coil after the bolt is tight. Is that normal?

 

515's are the original version although I think some were 'welded' instead of press fitted. The current version are SP-546. I don't know anything about them. But the whole breakage problem goes away if you do 60k mile plug changes and keep the carbon accumulation cleaned out of the extended hole each plug change. ( blow off everything the TSB says).

The dirt/gravel in the well is a problem. Holds moisture / oil residue and deteriorates boots. Sometimes turns to almost cement. We've had some members have to use a hole saw to break it up.

The COP hold down bolt being stripped is no problem if it will hold it in place. It plays no part in grounding or electrical circuit.

Good Luck

 

The coil bolt want stripped. It tightened down but the coils would still move around some like it wasn't fully pressing it down. I found 2 bores that had sorry all in them in total. Blew then out and blew it out again after putting the new plugs in, new boots and springs. Just tested it and it runs like a champ. No broken plus but getting them all out was fun. Sounds like this engine sucks a lot of air at full throttle now that I can test it.